I think you might have a bit of anxiety. the way you describe any negative thought or memory pulling you back down reminds me a lot of myself. the good news is that there are lots of strategies for dealing with anxiety, and a shrink can help point you in the right direction. hack your brain!
Fuck that shit.
You asked for help. You got excellent advice from many people here. Then you came up with excuses for not taking that advice.
Forget "social stigma". Forget the past. Forget your perceived weaknesses. Forget your excuses.
You are obviously smart and want to help yourself, otherwise you wouldn't have posted here to begin with. You need someone qualified to talk to (in person, not here). Do it and recapture your life.
Things are never as bad as they seem when you're at a low point. You will soon discover that once you take action. Do it now. Best wishes.
I have visited a psychiatrists with my problems anyway, and it definitely helped. Also, most of my friends know about that and I never had any problems, but that's probably thanks to my choice of friends. If you pick carefully you should have no problem.
Think about it like that -- visiting a shrink might cause your some problems, if it gets known in wrong places, and hopefully you can move elsewhere when that happens -- a harsh solution, definitely painful, but usually not the end of the world.
Your current condition definitely causes problems for you right now. Also, you can't just move away from your current problems.