This is an excellent answer. I've been in a similar situation myself: I eventually left. That was the best thing I ever did. It took me about a year to recover. Just as jblow, I'm a totally different person now (extremely confident, and I don't suffer fools).

Since then I've met some amazing developers who (unbeknown to them) helped me get past the mental block that the OP has described; people who could actually challenge me on a technical level, and who weren't jerks.

Take JBlow's advice, and I strongly advise you to take a month off of work if you can. You need that time to recover, recharge, and take a break.