I know what it feels like to face failure. It sounds like you've got those negative messages on blast in your mind, constant repeating themselves. I know when I'm especially depressed, I feel dumber, distracted, clumsy, and yell at myself for little things like bumping into a counter or tripping on a crack in the sidewalk. I withdraw from people and hide my nose in a book during lunch, and try not to make eye contact with my coworkers.
This is a good place to come for safe and open ranting. I'm glad you're here. Good luck.