What does it mean if I had empty sac on week 7 8 but my HCG levels continue to grow from one week to another rising to 22000 level?

An empty sac at 7-8 weeks, known as a "blighted ovum," can indicate that the embryo did not develop. However, rising HCG levels suggest that the body is still responding as if a pregnancy is ongoing. It's essential to follow up with your healthcare provider, as they can perform additional assessments, such as an ultrasound, to determine the viability of the pregnancy and the next steps.