I m on birth control and have been taking it regularly for the past four months. I always get my periods on the last week (the placebo week) but this time I didn t get it, it s just very light brown spotting. I had cellulitis in my foot and had to take clindamycan three times a day for 10 days. I ended those pills on 7/20 and should have gotten my period on 7/24. I did have unprotected sex on 7/23 and am worried. I don t know if the spotting and missed period is a result of pregnancy or if the antibidocs could be affecting my menstrual cycle. Is it normal for my period to not come after taking the antibiotic? or should I be worried about pregnancy?