Depo shot/period confusion 🤷🏻‍♀️

Okay so I’ve been on the depo shot for about 6 or 7 months now. When I got my first shot (August 1st) I was not on my period (idk if that really matters or not). I should’ve started my period very soon though. I waited 5 weeks later for my period to come. But while I waited I kept having really really bad stomach pain. It was like I was on my period but no blood was coming out. When my period finally came it lasted about two and half weeks! When that ended I got my second shot about 3 weeks later (October 17th). I haven’t had another period since the long one ended. Now every time my boyfriend and I have sex I bleed. I don’t bleed any other time except when we have sex. Last time it happened I went to the bathroom to clean up and there was no blood on the toilet paper. I’m going to my doctor soon but I just wanted some other advice first. Thanks in advance!????