There's no need to be afraid of seeing a doctor/GP. Part of their profession is to not judge. I was in a similar situation for a while very recently, I was also scared that whoever I decided to get help from would say that it's all in my mind and I'm just being immature, but honestly, the best decision I made was to start seeing a counsellor. I've noticed changes in my everyday life. I break down a lot less, I'm thinking a lot more positively, and life has just gotten better. I won't say that I'm 100% cured after 2 counselling sessions, but really, it has made a difference.
All the best to you, and take care.