Sorry to hear, GB Otis. Did the senior partner say anything to you--i.e., is it possible you're overestimating how much you sucked? In any case, think it's most important not to dwell on the fact that it happened so much as figuring out why it happened and ensuring that you don't put yourself in that position again. You'll get 'em next time.
The "senior" partner is only 7 or 8 years older than I am. We all agreed it was rocky. In the end, we got the result we needed to get, so it's not the end of the world in that sense. It's more just how I personally looked through it all, and the fact that the client thinks I'm awful at this, that has me off kilter.
Short answer: I think I'm just juggling too much right now, at work alone but also at home, and I think I wasn't prepared enough. Can't really make excuses.