I started playing Sit n Gos at Full Tilt with the $50 from PokerStrategy. I did really great for a while, building my bankroll up to $225 from playing $2 then moving up to $6 later on. I stuck with $6 for a while, but then I went through a major downswing so I moved back to $2, but from then on I've still been on a losing streak. My bankroll is now at $20.
I will admit that I hadn't used ICM at the start. I tried it today and got about 87% on my first time. Afterwards, I tried my luck again, 4-tabling $2 sit n gos, but only managed to come 2nd in one game.
Here's my ugly graph

Can anyone offer me some advice on what to do? I honestly feel that my game hasn't gotten all that worse, but I don't know anymore. It's like I 'forgot' what I was doing before when I won. Any help would be appreciated.