Hcg numbers rising not doubling

I’m 5 week 4 days today - I went to the ER yesterday due to HCG levels rising but not doubling and right sided pain. Numbers Wednesday afternoon were 1049 and Friday morning were 1564.

They did a transvaginal US and it’s not ectopic (thank goodness). They saw a sac but nothing in it. The doctor said numbers don’t always double and it is probably just too early to see anything. She said it could all be fine, it could be a blighted ovum, or I could miscarry. Time will tell.

I go back in Monday for more labs.

Just curious if anyone else has a similar story of numbers rising but not doubling. What was your outcome?