Hello, Depot Medroxy Progesterone Acetate results in complete absence of menstrual cycles (ammenorrhea). Depending upon the duration of its use, it takes around 6 to 30 months on the average for the return of fertility (ovulatory cycle), after discontinuation of Depo. Since you are off from Depo only a month back, the chances of pregnancy are minimal. Plan B is a morning after pill used as emergency contraceptive & contains Levonorgestrel, the progesterone. The total dose of 1.5mg (2tab. each contains 0.75mg) is higher than the dose of progesterone found in the combined oral contraceptive pills & hence it is very effective in preventing the conception. Levonorgesterol has luteolytic action & prevents the implantation of fertilised egg (ovum) by altering the endometrial lining of uterus. The symptoms you are experiencing are due to Plan B. Progesterone causes many GIT side effects like bloating sensation, nausea, vomiting, diarrhoea & esophageal reflux. symptoms are usually less if the pill is taken after food.