can't stop worrying that I'll MC

So I had a MMC in November that ended with d+c 29/11. I didn't have anything like a period until the 2nd of Jan but it was so light and barely last 2 days. I was opk testing and got a positive on the 20th of Jan. I got my faint positive on the 2nd of Feb with an early pregnancy test. Now I was having pains so went to the EPU to check it wasn't ectopic (it isn't) BUT they did say I'm barely 4-5 weeks pregnant. They saw a yolk sac but nothing else. I'm supposed to be 5+6 today based on when ovulated. they also found 2 sacs but one was about 1/3 of the size of the other and they couldn't see anything in it. I'm so worried because last time I had an early scan and they put my dates back. the baby then didn't develop after 6 weeks. I'm so worried it a happening again. Is it possible for my dates to be so far out?