Early scan??

Hi

I’m pregnant with my 4th and had an early scan yesterday morning and could only see the sac and nothing else in it so they did bloods and my hcg levels are 25000 and then did them again and they’ve gone up and due again so more tomorrow so every 48hrs there testing them. They said I look like I’m only 4 weeks because of the size of the sac as that’s why we can’t see anything on the scan and will be scanned again next week to check again I just hope it’s all ok? But has anyone had there hcg levels this high at this early or pregnancy? I never found out early with any of my other children so it’s all new to me thanks 😊