Hi Acscr
Do you color or perm your hair??? If so it could be damage from that.
Austen has a good point with the TE so you might want to check that out on google.
Meds can play a role in hair loss and you've changed your diet... so there are a few contributing factors. Hormones also need to be figured in and vitiman difficenties can really mess with your hair.
I used to be a hairdresser and I've seen people's hair change for lots of different reasons. In my professional opinion you should cut it and if you're using any chemicals on it, stop doing that. Give it a break (no pun intended) for a while.
My hair falls out a lot. I don't know what causes it.. but there are times when I feel like I shedding for the up coming season, what ever it may be. So now I'm keeping it a bit shorter and at least I'm not picking long hairs off of everything all the time.
Sorry you're going through this, I know how scary it can be.. I wish I had an answer, but it really could be so many different things.
Take care,