Super high hcg but nothing on ultrasound

M
This is my first, so I am scared about anything and everything. I just got off the pill about 4-6 months ago and have been TTC since. It has been a rollercoaster since every time my period is late I think I'm pregnant and later realize that it's just my period trying to adjust not being on the pill. So, after some disappointment and weird cycles I decided to stop actively TTC and let my period just adjust for a little while. Last week I was feeling like my period was going to be early. Some cramping, mood swings, and horrible breast pain. I couldn't sleep for 3 nights because no matter what I did my boobs would get in the way and hurt like the end of times. So just for kicks and giggles I decided to take a hpt and get my first BFP. It was a week before my period was supposed to even be here! And it wasn't a faint line, it was big and bright. So I start calculating and was not sure if my last period was then a real period since everything has been so messed up. So I call the doc and tell them that I'm either 5 weeks or 10 weeks. They do an internal sonogram and they can't see anything. Nothing. No sac no baby. Just my uterus. They ask if I could've ovulated late, which would put me closer to 4 weeks. Yeah. That's a possibility. My period has been a disaster since I got off the pill. They tell me to get blood work done so that they can monitor the hcg and see if it doubles in two days like it's supposed to. So I get the results from yesterday's: >10,000! I read online and everywhere it says that after 1500 you should be able to see a sac. And is it possible that I'm only 4 weeks and with that much hormones going on??? I don't get the next one done till tomorrow, so I may have to wait all weekend to get a little answer. And DH is on a business trip and I'm between jobs, so I am all alone in the house freaking out about this and worrying that it might not be a viable pregnancy. Dora's anyone out there know more about this? Has this happened to one of you before? I just need to know if this could be "normal" or if I need to rush to the doctor again.