For the last 2 days(Dec 1-2) not long after having sex, I've been bleeding lightly(bright red) that is barely enough for a panty liner, and been having some mild pains in my lower abdomen on the right side. The bleeding only lasts for a few hours and the pain lasts for less than 2 hours. I've had my period(Nov 24th-30th) Been off birth control for a month now, as my bf and I are trying conceive. Had my annual exam 2 1/2 weeks ago, and everything was normal. What could be causing this?