Blighted ovum

I'm nervous about a possible blighted ovum. I'm new to this I never even heard of this until I googled. A few things. 😧 (shouldn't have) so last Monday my levels where 828 ..yesterday they were a 9180. Last Friday the ultrasound tech said I was 4 weeks maybe 5. But there was no yolk sac or heart beat. But not to worry. My doctors nurse said today she thinks I would be 6 weeks. My next appointment isn't until April 10. Soo Is it common to see only the embryonic sac right now. am I overreacting??? Should I just relax. Every little thing freaks me out because I lost 5 babies.