So confused

Mercedes

I went to the er yesterday for some very bad cramping. They said according to my last period i should be 6 weeks exactly. Well when they did the ultrasound they did not see anything in my uterus or my tubes. My hcg level was 3066.1 they said they aren't sure what's happening since I haven't had any bleeding. I was told to come back in 48hrs so they can compare my hcg levels. They seemed confused and I am very confused as to what is happening. Does anybody have any insight on what could be happening?