How long does nicotine stay in milk?

New member. Please don't comment on what a horrible mother I am. I'm currently feeding my baby, however, I had 2 beer and smoked half a cigarette (it was an organic American Spirit, not that it probably matters) and I'm extremely worried. I bought organic formula from a health food store with no synthetic DHA in it and I was reading labels for about 15 minutes trying to find the right one, which I am using just for tonight. My question is, how long will the nicotine stay in my system? It was a HUGE mistake, I'm very embarred and angry at myself. I just don't want any of the nicotine to effect my baby. Any advice is appreciated!!