Nooo, not medic. Rather support.
A good squad will already have a medic who knows his chops, but rarely a support. Go support and hang back.
BF2 is not a kind place to n00bies who think rambo style works like it does in the movies
As for killing tanks with a pistol - you can't - more than likely you were eryx'd and the guy switched to pistols before you blew up.
A few points which will make you feel more at home:
1. If you want to fly choppers/jets. Practice offline in SP mode (fire up your own server and practice there). The bots will fly a chopper for you if you want to practice gunning.
2. Queue. If someone is waiting for a chopper or jet or tank, then let them have it. Stand back off the pad and don't crowd them out. Your turn WILL come and it causes less stress all round.
If someone runs infront of you and jumps the queue, don't force a TK, just get hold of an admin (if there is one present, look for the SGS tags), and let them sort it out.
I know the temptation is huge to want to fly choppers and jets straight off the bat, but it does take time to learn, so try and do so when the servers are quieter. You'll probably last longer too

Best thing to do, is join a squad who are using the bomber, or chopper and ask, nicely, if it would be possible to ride along with them in turns..
3. Don't be a tard. Play hard and play fair and people will respect you. I don't know how old you are, but many young kids come on the servers and behave like total spoilt brats (actually even adults do this!).
4. Join a squad, ask if the SL needs any sort of kit, and stick with the squad.
5. VOIP is a must, but till you get to know the guys, don't get verbal diaherra, I can think of one new player currently who is 100% annoying with his constant 'omg I got killed, omg I shot that guy, oms how did he do that...' but don't be shy either
I know it seems like you're getting your arse handed to you every 5 seconds, but you'll get to know the game and get better and find it's the finest game in all Christendom
