As for nerves...
I still get a slight case of them before performances, but I think that's due to the excitement of the evening (first preview, opening night). However, when I was doing more solo and accompanying work, like DR Danise, my nerves would kick in more after the performance rather than before. I guess I really was keeping things under control beforehand, heh?
Lately, nerves will kick in when I'm about to meet someone "important". I'm not debilitated by them, but they do make me sort of giddy and giggly. This usually happens when I'm playing auditions and I notice a "star" coming in - "I get to play for HIM/HER?!?!?" -And then I calm down when I realize that they're usually dealing with nerves too.