Having high hcg does not necessarily mean you're having twins. Wait until you get an ultrasound.
I agree HCG isn't reliable for that.
How many days past a what day transfer are you?
Example: my hcg 11 days past a 5 day transfer was 296.
2 days later, 13dp5dt. Was 539....I had twins
No transfer natural pregnancy after miscarriage! 179 two days later 541 then 3 days 3019! I'm 3 weeks and counting