Just for the record, I've been vegetarian my entire life and I don't shed much hair.

I really don't know what to tell you. 50% of your hair in 10 years is A LOT of hair. Have you tried speaking to a doctor, maybe a dermatologist? I mean it could be diet, but there might be some genetic factors in there are well. Do you have any family members with this issue? Well, best of luck to you. I'd definitely go talk to a professional though, even if it's just for a second opinion. For now, maybe just try to get a lot of fruits and veggies in your diet and do low manipulation hairstyles.
Mostly 3c and lovin' my curls

This is not a fashion trend, it's not a statement, it's pride for who we are and what we look like. And that is where our true beauty shines.