Back pain in early pregnancy

I found out the beginning of the week that I’m pregnant with baby 2!

Going off of how the midwives calculate it from first day of your last period I’m 5 weeks but I could be less. I was being sick badly Christmas morning and Boxing Day morning so could be true!

But me and my partner did a test Boxing Day and it was negative. But it was one that had given false positives and negatives to others before 😩

When I conceived my first I felt so much pain front and back but this time I’m only feeling so much pain in my back and it’s horrific!

Has anyone else just had back pain early on and was it normal or shall I go doctors?

Thank you in advance!x