Period going on 3 weeks. Send help!

My period started on September 24 which started very light. I started the estrogen patch and pill on September 25 for my frozen embryo transfer(FET). My daughter still nurse here and there but she’s eating what we eat and mainly does it for soothing. Well, today I am still bleeding like a period with clots. I had a second u/s last week and they said it looks as if I’m in the middle of my cycle but they didn’t see anything concerning and we ended up canceling the transfer appt.

I must say, my period was late as it usually comes on the 4th or 5th but this time it came 20 days later. I’m not cramping, I took a pregnancy test around September 10 and it was negative. I’m so confused as to why I’m bleeding. I also had a endometrial biopsy a month or so ago that was horrific, she ended up doing the scratch 4 times since it was too much lube from the u/s probe going into the tubes instead of blood.

Please share stories if this has happened to you.

This is a picture of a clot that fell out of me as I was getting out the shower.