Mini Pill experiences

So I'm deciding if I should get on the mini pill. About two months ago I started on it, and about two or three weeks into taking it I started experiencing bleeding during sex, every single time we had sex, and I would really only bleed while having sex. Would stop as soon as we finished. This made the guy I am dating extremely paranoid, and worried about me, and I decided to stop taking it (we were still using condoms anyways). After I stopped I never experienced the bleeding again. I also went to Planed Parenthood where I got my prescription, and told them what happened. They said they don't think it was from the mini pill, and I shouldn't worry, that it was probably nothing unless it keeps on happening. Has anyone else experienced this on the mini pill? I'm now tempted to start taking it again, because I have now been dating my guy for 4 months, and neither of us are sleeping with anyone else. Please only respond with your experiences with the mini pill. I have an autoimmune disease, and that is really my only safe option without screwing up my hormones.