Patrick, welcome to the forum.
You see, I really understand your situation. I may say the last... 3 years, maybe 2 and a half, I used to deal with the same stuff (Frustation, needing breaks, comparing myself with some other people, paying attention to tiny details in an obsesive wat). I was so worried about achieving perfection, that I could never get it. Cuz I was always stressed, pissed off, I couldn't deal with myself.
Then one question came to my mind... "Are you enjoying this? When did you stop enjoying what you are doing?" I figured out that I live the the last 3 years without enjoying a single day.
I don't know, maybe this is not your case. But it doesn't sound like you are enjoying it.
Don't push your self too much. It's okay to work hard, but with that kind of obsesion you are only limiting yourself. You won't be able to get the next level, to achieve what you look for, without enjoying what you are doing. All the energy you can be spending in doing something great, you are wasting it in worrying, getting stressed, obfuscating... imagine just what you will be able to do if you only focus your energy into positive things.
Dunno, sorry if I'm misunderstanding the situation, I just want to help.
PS: By the way, I think your paitings are terrific ^^