Advice needed for a youngin

A little background...I'm a 19 year old college soph who plays poker in my spare time. I could give you the "I'm a student of the game spiel" but I've heard it a million times.

I am by no means an amazing player but I am definetly improving. Herein lies my problem. I started the semester with a set bankroll for poker that I have been maintaining. I started with $1000 and have been run down to the felt and back up to $3000 and back to about even now. My big scores have come from two MTT wins, and another few high finishes. I then seem to lose it back in cash games where my style isn't translating over well enough. Is it possible for me to maintain a bankroll playing solely MTTs and maybe SNGs if I had to. I sometimes lack the patience for SNGs(even though I can play MTTs) and don't really look forward to grinding them out 4 tabling. Any advice would be appreciated.

I'll continue to read the forums as you guys give amazing advice. I'll keep trying to contribute what I can.

Thanks all and g/l at the tables