(CNN) On Thursday, Claire Holland graduated from sixth grade. It was a happy day. She made the honor roll and she won her class' big science award, but her day was not without worries. The 12-year- old for Mandeville, Louisiana is caught up in the formula shortage that has left countless families across the country on edge. The shortage has even sent some children to the hospital, because they can't get enough nutrition.
Holland has what's known as tyrosinemia. It means that her body cannot metabolize a specific amino acid called tyrosine. To survive, she has to eat an extremely low protein diet supplemented with a special formula made by Abbott. The formula called Tyrex-2 is an amino acid modified medical food. Without it she won't get enough vitamins and nutrients that most people would get from regular food.
Holland has been living on this formula her entire life. In February, when Abbott had to shut down its plant in Sturgis, Michigan, her formula wasn't recalled, but it got stuck at the plant. It meant Holland had to ration how much formula she relies on every day.
Holland's using about half of the formula she'd normally eat.
"We just wanted to try to make it last a little longer," said her mother Shannon Holland.
Her mother said that they have been working with Claire's nutritionist at Tulane to make sure she's getting enough of the nutrition she needs.
"It's a little scary," Shannon Holland said. "We only have a case of formula left and we didn't know how long this was going to last."
It could take months before the nation's supply goes back to normal. Currently, 45% of baby formula products nationwide were out of stock at some point for the week ending May 15, according to figures provided to CNN by Datasemby, a real-time data-tracking agency that gauges how much product is on store shelves.
"It's still just the unknown of how long this is going to take and not being able to find a suitable substitute for her is very stressful," Holland said. "It's taken a toll on (my daughter) as well."
The Hollands are not the only family stressed by the shortage.
Renee Steiber who lives in the Chicago suburbs said she had to start rationing the formula her son, Owen, used. Finding his specialized formula, Necotate Jr., became a full-time job.
Her 11-year-old relies on the formula. It's made by Nutricia, not Abbott, but when Abbott's customers couldn't get their formula they switched over to Owen's.
"Basically, they kind of took up the supply was getting every month," Steiber said.
Owen typically gets formula four times a day through a feeding tube. He can eat very few solid foods because he has Eosinophilic esophagitis (EoE), a rare disease in which his body is essentially allergic to many foods. Unlike standard food allergies that give a person hives or anaphylaxis, when a person with EoE eats food they are allergic to, it causes chronic inflammation in their esophagus, so much so that the person can't swallow.
Steiber had about five days worth of formula left, when his mom called the supplier like she always did to re-order. It was the first time she heard they didn't have any. "I was like, 'Oh my God, you're kidding me,'" Steiber said.
She spent the next several days calling every pharmacy in the area, asking out-of-town relatives to look for it, and searching for it online.
"The problem is, whenever I'd find something by the time I would type in my credit card, it would disappear and sell out," Steiber said.
Steiber said she ended up giving her son one less feeding a day.
"I was trying to just stretch it out as much as I could," Steiber said.
For the last feeding of the evening, she said she was just giving him water instead of formula.
"I know it's not the best nutritionally but at least it helps him feel full," Steiber said.
Fortunately, Steiber added Owen hasn't lost any weight. And he has his usual good energy she said.
"But I know it's not ideal because it's his main nutrition," Steiber said. She's been working with a nutritionist at Ann & Robert H. Lurie Children's Hospital in Chicago to figure out alternatives for Owen that provide more calories and also give more table salt to this diet. The nutritionist also was able to find a new company to provide some additional formula. "But no one knows how long that supply will last," Steiber said.
Danone, the company that makes Neocate Junior. - the original formula Steiber used - said in a statement to CNN that it has increased production and shipments to the US.
"We understand how important it is for families to access these specialized formulas, so it's been our absolute priority to increase production and supply since the shortages arose in February," the company said.
Dr Joshua Wechsler, an attending physician at Lurie Children's Hospital's division of gastroenterology, hepatology and nutrition, specializes in EoE. He has heard from several patients who have chosen to ration the formula that they have -- and have been doing so since late February, or early March.
"You know, we saw a lot of weight loss among our patients, because they frankly didn't have a choice but to ration," Wechsler said. "And there just wasn't much we could do."
Wechsler said he understands that parents are doing whatever they have to do to make the situation work. From a medical standpoint, it is definitely not ideal.
Dr. Sahira Long, a pediatrician and lactation consultant at Children's National Hospital in Washington DC, says with older children and even older babies who can eat some solid foods, rationing isn't ideal, but it's "really going to be okay."
"When there's a shortage, you have to do things a little bit differently," Long said.
"For children younger than six months it's a little riskier," Long said. "You want to make sure that they're getting a minimal amount of calories and your pediatrician can help you calculate that."
Long said what parents definitely want to avoid is putting less powder or water into their formula to make it last longer. "That can be really dangerous for babies," Long said.
Long said she's also hearing from families that are considering making their own formula, but she advises against that. "Honestly, the recipes that I've heard of circulating on the internet make me cringe," Long said.
Holland said she lucked out recently when a dietician at Tulane called Abbott on their behalf. Not two days later they had a case of formula delivered to their door. After that two month supply runs out they aren't sure what will happen next. They say their dietician asked Abbott for a date on when another case could be sent, but they did not get an answer. When asked about this, Abbott told CNN that on a case by case basis, the company is releasing limited quantities of metabolic nutrition formulas that were previously on hold for urgent patient needs.
"Our number one priority is getting infants and families the high-quality formulas they need, and we are working with the FDA to quickly and safely re-open the facility so we can ease the nationwide formula shortage," Abbott said in an email.
But until the formula situation is straightened out Long and Wechsler recommend that families that are considering rationing their formula should really talk to their pediatricians first to determine what the right approach is.
"Don't try to do this alone at home," Long said.