Please help !!!

I took a pregnancy test last Monday and it came out positive, I been having cramping on my lower stomach but nothing big. On Sunday I was working and when I went to the restroom I noticed I was spotting . I went to the er immediately. They did test and ultra sounds and all they told me was that my uterus was thick but they didn't find anything in there so I had 2 possible things happened . The first is that I'm pregnant but it's very very early the second is that I'm going through a miscarriage. My hormone levels were low so they wouldn't tell me anything. I have a doctors appointment Thursday so they can tell me if its progressed or if it's done . Has this happened to anyone ?