My husband and I are TTC and I am still trying to figure out what could possible be/not be pregnancy with PCOS.

Recently I had some slight bleeding during sex. I wasn’t too worried about it since it has happened before and it was my period starting. I threw in a tampon and called it good. I woke up the next morning and the bleeding had stopped. Fast forward almost two days later, I look inside my underwear just in case it did happen and I see a dark streak that smelled like blood inside. I’m not really sure what this is. I’ve been having cramps since the first time I bled a little and now, they’re slowly intensifying. My period usually comes late and it’s hard to know when my next cycle will begin. Is this just my period or is this implantation?