Miscarriage at 4 weeks- HCG doubling?

Emily

I found out I was pregnant on February 20th, and started heavily bleeding February 21st. OBGYN did a pelvic exam on February 22nd and told me it looked like a miscarriage, and that I was most likely going to pass it naturally. She ordered bloodwork done to make sure my HCG was going down... but it’s not going down, it’s actually doubling. 2/22 my hcg was 30, 2/24 my HCG was 74, and 2/25 I went to the ER with extreme stomach pain, my hcg was 103. They did an ultrasound and said there was no evidence of an ectopic pregnancy, or a normal pregnancy, and no evidence of tissue that was left behind. I’m still spotting a little. Has anyone experienced this? Even my doctors can’t give me answers and I’m going in today for more bloodwork. I just want this experience to be behind me so I can TTC again and finish grieving.