Possible miscarriage

I got my IUD taken out January 13th 2016, after having it in for almost two years. Before that I was on the birth control pill for around 4 years. My first period came January 16 (I never had a period with the IUD and always had irregular periods before that. I also have PCOS). My husband and I decided to start trying for a baby. My next period was due 2/13 but never came. I assumed my cycle was just irregular again, but about a week later I started feeling nauseous, incredibly exhausted, and my boobs hurt SO BAD. I took a test 2/28 and it had a vvf line. I took another test the next morning, and it was faint still but definitely positive. I went later that day to my doctor where I took another urine test which also came back positive. Hubs and I were SO excited! I was concerned about being able to get pregnant since I always had an irregular cycle and PCOS, but it happened so fast! I immediately started using every baby app I could find to figure out how far along I was. Everything was saying 6 weeks, due 10/22 based on my LMP. Fast forward to Thursday morning 3/10. According to my LMP I should've been 7 weeks 5 days. I woke up to go pee and when I wiped there was a noticeable amount of bright red blood on the toilet paper. This being my first pregnancy, I instantly freaked out and started googling what it could mean. I eventually called my doctor and they had me come in. After what felt like forever, I was finally given a transvaginal ultrasound. There was nothing on the ultrasound; no sac, no baby, nothing except blood in my uterus. The doctor says this is indicative of 2 things. 1) I'm just earlier along than we thought or 2) I am miscarrying. She had me take a blood test to test my HCG levels which came back at 4665. I have to wait until until Monday to get my labs done again to see if my levels have increased. I'm very worried that I may be miscarrying. Has anyone had this happen to them? I don't have any other "weird" symptoms, haven't had any more bleeding or cramping. My biggest concern is the blood in my uterus. Is this normal? Any advice you have is much appreciated!