Concerned

I went for an ultrasound yesterday to rule out ectopic and the doctor said we should have been able to see everything and maybe even a heartbeat. My hcg levels are so high at 16,000 for 5+2 weeks and that’s why he said that. We only saw an empty gest sac which was good to at least see that but now I’m a little concerned for another blighted ovum because my symptoms have all pretty much disappeared for day minus some slight tenderness to my boobs and nipples. Anyone else ever experience anything like this?