I'm a 20 year old female and I have recently been experiencing extreme hair loss, fatigue, frequent thirst, and moodiness. As a child, I had thick long, healthy hair.Throughout my teen years I excessively straightened it blow dried it on the highest setting. I'm currently trying to let it grow back naturally but it's not working. My hair is now very thin and my scalp is visible from every angle. It's embarassing. Is this a vitamin deficiency or did I stunt my hair growth? It's not growing back at all... What can I do?