Cash Tables Vs. Tournys

[JDMcNugent7]

I do pretty decent at Sit N' Go's which i tend to play alot. I decided to start playing some cash games(which i am new at) with my winnings this month - i thought they would be the same thing pretty much but my results are no where near the same:

In Sit N' Go's i have made $250 in the last month
In cash games i have Lost $180 the last month

I need advice on the difference between these two types of play and how can i get better at cash games ?

Thx