8-9 weeks backache and cramps

I had a scan a few days ago, good heart beat and measuring at 8+4 and was reassured.

But im concerned that now and then I get aches in my lower back and mild period like cramps in my lower tummy. More so if I've been on my feet doing a lot

Is it normal because of uterus expanding?

Are others experiencing this?

I'm not bleeding.

having first pregnancy nerves...

Thanks