One more note on the volume issue. Your amp is going to be a lot louder to someone standing 10-20 feet in front of it than it will to you standing 1-4 feet away from it. You don't have ears in the back's of your legs you know. I suggest finding some way to tilt your amp back a little so it's pointing at your head. Try it and see what happens.

As far as the other goes, I'd much rather play with someone who's a lot better than me than equal or worse. You'll learn more that way. I love being a rythm guitarist myself. The way I look at it is, if it weren't for me, the lead guitarist wouldn't sound so good. It's a team effort, work together to create the overall sound of things.