Terrible anxiety

6 weeks today. Just found out my sister in law is 10 weeks (post IVF. A blessing for them.) I talked to my BIL and he said how I'm still so early and that they have already heard a healthy heartbeat twice. Our first ultrasound is next Monday. For some reason after talking to him now I am even more terrified about having a missed miscarriage. Where If I go to my US and there's no baby or heartbeat??? My levels were good when I last did bloodwork. 2,640 hcg at 4 weeks and 6 days. I'm healthy and this is my first pregnancy. We want this more than life itself. Can anyone offer comforting words ???😥