I'm in over my head.

About a week ago I jumped into a stock called MEDX after seeing it on CNBC's Fast Money. It had recently gained about 7% on news of a new anti cancer drug. I acted on emotion and greed. Don't make the same mistake. Not only did I deviate from my disciplined monthly investing of a small sum in a diversified index fund, but I payed a whopping $10 commission to make a real time trade using Sharebuilder. Now I'm in the stock and will probably lose money because I have to make more than $20 just to break even.

Did you ever invest with your emotions rather than your brain?