It doesn't matter how well/poorly you perform in the game, the drops are purely chance-based. Pop a fireteam medallion on to boost your chances of an exotic (even if you're playing solo).
I know the feeling dude. I have played about 18 games of crucible in the last 2 days alone and have only won 3 despite dropping 20+ kills and having the highest damage/objective points. It takes the piss.