I had this and had an emergency scan just to find out thay it was my uterus and hips expanding
Your uterus is stretching quickly, and your embryo is burrowing in deeper and getting cozy :)
It is quite normal .
Congrats!
It might be implantation cramps
No problem. as lomg as your not bleeding my opinion is that you should be fine and congrats!
I googled it and the first thing that popped up in bold blacl letters was that this is a normal symptom at 8 weeks pregnant!! But if it gets worse and you are worried you should contact your DR.