I'll repeat what others have said: you're probably not a very good player.

At full ring tables full of loose opponents, with 5 or 6 players seeing the flop, it is incredibly easy to win. All you have to do is play tight preflop, fold when you don't have the pot odds to stay in, and bet and raise when you have a strong hand. That's it.

You can make all sorts of mistakes and still be a winning player, because your mistakes are cushioned by the fact that your opponents are pouring money onto the pot with very little chance of winning the hand.

Against tighter players, you have to actually outplay them after the flop to make money.

Go to the microlimits forum here and participate in the discussions about hands, use pokertracker if you're not using it already. Oh, and here's a tip: if the site you play at has 6max tables, try them instead of the full ring tables, that's where the loosest players can be found. I'm probably not a very good player either, but at .50/1.00 6max tables where half the players are seeing the flop, I can still easily win money.