So confused hcg levels?

So I’m so confused right now. This pregnancy is 100% different then my first and I’ve had an impeding feeling it wasn’t gonna stick. My tests took weeks to get dark and my hcg levels weren’t rising much and the ultrasound didn’t help get anymore answers. So my doctor sent me for bloodwork again

3 days time between all 3 test

5/18 6736

5/21 8321 (when I saw this one I immediately thought okay I’m gonna miscarry soon)

5/24 19,658 (then this came in and I’m like wtf)

Tell me I’m not going crazy like the 2nd one barely moved and then the 3rd double+