Hi. I Started Birth Control In Late May. I Had

Hi. I started birth control in late May. I had my first time having sex in the beginning of May, however, we used the pull out method which was successful. We broke up later that month and I am no longer sexually active. In the first few months of the birth control I had heavy periods that gradually got lighter and lighter with spotting. Now, for the past 2 months (so August, September) I have not had any bleeding. I've gained some weight but other than that there are no other symptoms. Could I still be pregnant?