Hcg levels; ultrasound

I had posted about this previously so this is more of an update

I had an ultrasound Thursday April 1. My last period was feb 10 which puts my ultrasound about 7 weeks. I was told the gestational sac was there (no yolk sac or fetal pole but the sac is small) and was measuring around 4 weeks. I was using ovulation tests and had my peak feb 23.

Still haven't heard from the doctor since April 2nd when he called about the ultrasound and he told me to do 3 blood tests yet he ordered 4 did the last one this morning ...

last Saturday hcg 23136, Monday 30504 and Wednesday 40903 ... he said a day or two in between ...

on March 20th my original level when going for first round of blood work was 805 and he said something abiut seeing if they drop and something abiut 500 ... he had said he might call after the second one.

I know hcg doesn't double at the levels mine are showing but im not quite sure how much should be increasing. Ive read after 6000 hcg may only double 4 or more days and is not as reliable to detect viable or non viable pregnancies. Any thoughts or anyone go thru something similar?