Hairs loss at 18. Please help.

Jules • Young married soldier just trying her best to keep everything together.
So I'm starting to panic. This is what I lost in the last shower I took. Everytime I wake up I wake up with a pile of my own hair on the pillow. Everytime I run my fingers through my hair I lose clumps. Everytime I brush my hair it happens. I feel so ugly knowing it's happening. It's so much hair I'm losing. I don't know what to do.
I've been looking it up online and it's mostly cause by a bad diet and stress. I fairly okay except when I'm stressed I tend to skip meals. I have been crazy stressed lately. I just finished high school, I'm moving out in two weeks, my parents are constantly picking fights with me, I start Basic Training in two months, my whole life is upside down. 
But maybe it's my birth control. I did a lot of research and was told that wth Aubra it's very rare to lose hair for it. 
I put my hair up in a pony tail a lot. That shouldn't be it though, should it?
I'm losing a lot of hair. My hair isn't noticably balding or anything, it's just a lot thinner. Also I've been on the birth control For over a month so wouldn't this have started earlier?
I don't know what to do. I've already had a full anxiety attack about this twice. It's stupid but I hate it. I feel overly vain when I get stressed about it. But seeing this much hair in my hand multiple times a day for a week or more Makes me feel so ugly. Honestly, it's made me cry twice. I don't want to keep losing hair. I've always had nice, thick hair. I'm sorry this is so long.