I don't know what's going on and I'm scared and confused.

I've had endo for 14+ years. Managed pain with no periods on Nuvaring for the last 9. I came off the ring back in April and it took until around July to start being more normal with cycles. Ever since July I've been pretty regular and have been <a href="https://play.google.com/store/apps/details?id=com.glow.android">tracking ovulation</a> and periods almost to a T with this app, temping and OPK's.

My pain has significantly increased each month, but has been predictable knowing which days of my period were the worst. I thought I was getting a good handle on all of it until I started ovulating this month. I ovulated on Nov 22. I normally have very very little spotting during ovulation and mild cramping. On the actual day I ovulated I had pain so bad it felt like I was on my period. The pain has been slowly increasing but I thought maybe it's just worse this month for some reason. This morning I woke up to a large dark blood clot when I used the restroom and have been bleeding bright red blood since, almost enough to need a tampon. I'm technically only 3 DPO but I went ahead and took a HPT just to eliminate anything and of course it was a BFN. I'm not sure if this is endo related or what but something is not right and feels very wrong.

Can anyone please give me any advice if I should do something or have any ideas of why this could be happening? Any information or suggestions would be greatly appreciated. TIA!