I'm a 26 year old cis female in a relationshipish/fwb thing with a cis male. We have piv sex fairly regularly, sometimes going a few weeks or so without, then it'll be more frequent. My problem/question/concern is that I always bleed after sex. It's not a lot and is only noticeable when I use the bathroom. It's for a few days after, too. Sometimes it's bright red blood, sometimes it's brown, which is typically what my withdrawal bleed is made up of. It's not a lubrication issue, which is what internet searching has told me. No diseases between either of us. I'm on Yaz, have been for about two years and take it as directed, and we don't use condoms.
This is a new thing, too. We've been together for just shy of two years and this has only started in the last couple of months. I feel like I'm constantly bleeding though, between this and then my withdrawal bleed. Anyone have any idea what could be causing this, and how to stop it? I occasionally skip bleeds on the Yaz, which does seem to have messed things up a bit (last time I skipped, I had serious breakthrough bleeding, like I hadn't even skipped), so I'm wondering if that's causing it? Although I don't understand why since again, I've been on it a while, skipped a bunch of times, had sex, and never had this happen.
Help? Any way I can stop always bleeding because this is incredibly frustrating.