** warning graphic photo** Please help, very confused

Can someone please help or give me some sort of advice? I am unable to get into my doctors till next week and I am very curious / slightly worried.

My period was 19 days late , I’m normally very regular but I’ve been stressed a lot so put it down to this. Prior to the 19th day I was feeling very fatigued, horrible tummy pains and always feeling nauseous. I did take a pregnancy test in this time frame for peace of mind but came back negative. On the 15th day I started spotting brown, so I thought okay period is starting so I put on a pad and so fourth, brown discharge continued for 4 days and was very light in flow. On the 19th day (day 1 of cycle) I started what I thought was my period, it was extremely light. There was only discharge when I wiped . Colour and flow was on the lighter side no PMS cramping just stomach pains. Day 2 same symptoms, later that night this came out of me and there was extra discharge surrounding it. But once again no PMS cramping, only reason I knew something happened is because I felt it. At first I thought it was a clot, once I inspected closer / felt it, it’s harder, squishy and felt like tissue. I’m now on day 4 and since this has happened I have had very weird stomach pains (not period pains - more higher in stomach ) and I have been feeling really nauseous fatigued and still quiet off. Bleeding has increased slightly but nowhere near like my normal periods

*Edit - I did have complete unprotected sex 2 months ago and a second time with my partner and he did ejaculate inside of me both times. A month ago i did start the pill a few days prior after being off of it for 6 months so I’m not 100% sure we were protected *

Could this be related???