HCG question

So as of today I’m about 4w1d maybe 4w2d. I got my bloodwork done Wednesday morning and levels were 150. They had me come back today to make sure levels doubled and they said my levels more then doubled in 2 days. My levels are now 499! Is this a good level to be at for 4 weeks? Someone mentioned kinda jokingly it could mean twins but I didn’t think it was possible to tell until an ultrasound.

I miscarried my first pregnancy at 6 weeks so I’m just trying to stay positive and praying this pregnancy sticks!