Blighted ovum twice ??

In 2017, I had a blighted ovum then got pregnant with my now two year old daughter who will be three in March.

I found out back in July I think towards the end I can’t remember, that I was pregnant again . We had our first appointment today but the ultrasound showed an empty sac, so they had me do blood work, to check my hcg levels in case I wasn’t far enough along to detect anything on ultrasound. I just called and they said my levels were rising about 20,000 but they still don’t know for sure so I have to go back Wednesday to have another blood test. Does having High hcg levels indicate any positivity? I really don’t want to go though another blighted ovum again. If it happens it happens but it’s still depressing. I’m just really worried .