Super nervous

I took a pregnancy test on October 5th because my period was late, and the test came back positive. Me and my boyfriend had only been trying for 3 months. I went for my first sonogram on October 31st, and based on my last period, I was supposed to be almost 8 weeks along. She did a transvaginal ultrasound and said she could see the sac, but no baby. My heart dropped. Then she told me that it's possible that I was just earlier than I thought so I started to have a little hope again. I went back 11 days later because of intense nausea and vomiting, and she did another ultrasound. This time she said she saw what looked like early fetal development but no heartbeat. She also said it looked like there was bleeding in my uterus. (By this time I was supposed to be almost 9 weeks) she said it looked like my body was trying to miscarry but she would monitor me closely over the next couple of weeks. I have another appointment this Wednesday and I'm so worried. Has this happened to anyone before? If so, how did it turn out? I don't have any cramping or bleeding at all, and I still am having all of my usual pregnancy symptoms.