Stressed. Bleeding. Low Hcg.

I’ve never been so worried in my life. According to my last menstrual cycle, I’m 5 weeks and 2 days. I went to my Obgyn yesterday because I’ve started experiencing spotting that has turned into BLEEDING today. She stated my Hcg levels were “abnormally” low but from Friday to yesterday, it has doubled. I’m scared I am or will miscarry. The ultrasound did not show a sac in the uterus. Hoping the bleeding isn’t a miscarriage and I’m just not as far along.