Went back for bloods today and my levels were at 440. So they didn't quite double since my last?

07/21-28.4

07/23-51.8

07/27-275

Today-440

However according to my first blood draw doing the math that way it's more than what I should be at rn. It's all confusing honestly. All I know is the levels are technically rising. Still nothing on ultrasound, a little bit of fluid in my uterus now that MAY turn into a sac at right now who knows. I am having to go back next week and every week after that until we figure this out. Anyone else have to go through this??