What helps me is to think: Ok, I screwed up, now let's take charge, figure out what exactly went wrong, and find out how to prevent it from happening again. I

What helps me is to think: Ok, I screwed up, now let's take charge, figure out what exactly went wrong, and find out how to prevent it from happening again. I would write a document stating exactly what went wrong, based on that suggest measures and changes to prevent this from happening again in the future. Be brutally honest, but refrain from playing the blame game, do include your own mistakes, be as objective and fair as possible. You could also see if you can salvage your project in anyway and suggest how to move forward. Usability issues can be solved, technical choices can be changed. For either option there should be broad support. If not it might give you more insight in the "politicking" that's going on. Also realize that people make mistakes, nobody is perfect. The best you can do is learn and move on. Beating yourself up over it won't help you in any way. Don't be mean to yourself, be honest but in a kind and empathic manner. Anyway, it sucks, especially with politics involved, hope you can move on from it. Good luck!