I Had FET On January 14. I Had Positive Hcg

I had FET on january 14. I had positive hcg 50 on 11 day post FET. HCG went to 69 after 48 hrs. I ended up miscarrying, I believe I passed something, grayish and bloody on Feb 4th. I have been having back ache, pelvic pain, and rectum pain since. It comes and goes. Sometimes it's like a stabbing pain and pretty intense and other times it is just an annoyance.