Slow rising HCG then faster?

Se

I’m wondering if anyone’s been in a similar situation. I don’t have an ultrasound for a few days.

My beta hcg results were as follows

4+6 3340

Then 48hrs later

5+1 4382

Then 40hrs later

5+3 6310

So my rate of increase seemed to be slower earlier and now it’s sped up?

Has anyone had this and can shed any light? Vanishing twin?? Just slow rising levels?

I have no symptoms of mc. I have sore boobs/nipples and fatigue.

Any help appreciated 🙏