[M.B.E.]

I agree that you should have pushed in preflop although I'd say it's somewhat close. If your stack had been 4000 rather than 3000, I think your raise to 1200 is okay. (For one thing, if you're confident of your read of the BB, you'd be able to fold to a reraise from him.)

When the SB (who you said was aggressive) reraised to 2000, you should have reraised all in. Very unlikely he's going to fold to the reraise preflop (which would only be 1000 more), but you don't want him to be able to get away from his hand on the flop if he has a small pair. For example, if he has pocket fours and the flop comes A-K-T, it's easy for him to fold and save the 1000.