Bleeding during sex😓

Hey guys, I'm 17 and for year and year I've been in and out of the doctors about my periods and how irregular they are. I know most girls have irregular periods, but I can go several months with out the suddenly Mother Nature hates me again, by every time I have sex with my partner I bleed, sometimes it can be a lot sometimes it can be so little. Does this happen to anyone else? I've tried different techniques, depth and length. These don't seem to affect wether I bleed or not, I just do after sex😓😓