As a girl, your hair will fall out. I also thought that it only happened to me and I couldn't understand why, but my friends are always complaining about losing hair. You lose on average 100 hairs a day. If you straighten or blow dry your hair on a regular basis -avoid doing it during the holidays. Wash your hair and let it dry naturally. Also, brush your hair when you wake up and before you go to sleep. Now that it's holidays, allow your hair to breathe. And by not messing with it so much, your hair should become more healthy as well as not fall out so much.
Washing hair all the time also makes it weak as you scrub the scalp and destroy the hair roots. You need to wash it once in a while, condition and moisturize it to give it nutrients. Eat healthy, avoid heat processes and combing it all the time. With these tips, your hair will be healthier and stronger.
Yes, diet is the best way to take care of your hair, and the rest of your body. I'm 49. I eat as healthy as my budget allows. Almost no McDonald's or anything like that. Almost no drinking. No smoking. No drugs. Try to walk once a day. And I sleep about 6 hours per day. I feel great. I'm 5' 10" and weigh 175 and I'm a man. A little on the heavy side. Do all of these things and you will fix your hair problem, and just about everything else in your life.