Measuring a week hehind but my HCG is sky high

Hi ladies,

I’m worried because I went for my first ultrasound at 7.5 based on my LMP but the tech adjusted baby to 6.5. I know this is common but my HCG levels were already off the charts at 133,000 at 7.5 weeks and now she’s saying I’m 133,000 at 6.5 weeks? It’s not twins and it’s not a molar pregnancy since we heard a heartbeat at 144 so what gives? Does anyone have experience with super high HCG levels and baby was born fine? I read on another post that it could mean down syndrome. Thinking of asking my Dr for another ultrasound to see if the tech measured incorrectly...what do you think?