Hair loss from weight loss?

i'm 13 and recently lost 53 pounds, in less then i year ( had to lose for medical reasons, was borderline obese), anyway i know that i lost weight to fast, but my weight was never dangerously low and i eat lots of protein, take vitamins and don't use Straighteners or lots of products, but my hair still continues to fall out. I also take hair vitamins, i am certain my hair loss is from rapid weight loss because i have had blood test done. what can i do to get my hair thick again and can i go completely bald at 13? Someone please help!