Advice please

My period came on Saturday the 30th ( a week late but I'm always irregular) this was my first period while being on the pill I started the pill over a month ago. My periods used to be very heavy but short only lasting 4-5 days. This time was different it lasted for a week and it was very very light ( I could wear the same pad all day and have 0 blood on it, but when I wiped there would be pink blood although I did wipe once and a large grey thing came out but I guess that could be my lining etc... the blood was never red). My period ended last Saturday morning (7th) and everything was fine, until yesterday every time I wipe there is now blood on the tissue ( not red but pink again ).. and droplets of blood in the toilet. I have PCOS and I also have a boyfriend and we are sexually active and he cums in me ( I'm on the pill I know it's 98% safe )... what could the bleeding be? It's scaring me a lot😟 sorry that this is long but idk what to do...