Hey Amanda, glad to hear about your 12 days, and good to see you in SA.
Thinking/hoping that/telling yourself that you can control or manage your addiction is apparently very common, someone put a great quote about it in a thread of mine recently, from the Big Book. Shame..shame kept me from going back to AA for over a year, and I regret it very much today. When I did come back, I was welcomed with smiles and 'glad you are back's, not judgment.
Many people there have been in the exact same situation. I hope you keep up the sobriety (:
At AA last night there was a girl who talked who is just about to turn 22, and she got her 10 month chip. Said it will be the first sober birthday for her since she was 13, and that her last one, her 21st, she ended up somehow cutting off a finger in her state of complete wastedness. So I agree with Intention, this might be the best birthday ever for you!