Has anyone experienced this?

I am 5 weeks and 1day pregnant,

On Monday I got a 2-3 week result on a digital

But 2 days later it’s now saying 3+. I have never gotten a 3+ until I was at least in my 6th week.

How come my HCG has shot up so much to change it so quickly? I’m obviously very chuffed but was curious as I know some people have said it could be twins but I’m not getting my hopes up as they are only tests.

It’s just I’ve never experienced it with both my other pregnancies at all