Extreme cramping, 21 weeks please help

I’m 21 weeks pregnant and have had constant really really strong cramping in my belly like intense period cramps for the last 2 hours.

I will have moments where the pain is a lot more intense for around 30 seconds, like a tightening feeling in my belly.

Tummy where baby is sitting is also sensitive to touch.

Back pain is horrendous.

I’m really worried about contacting my midwife.. this is my first pregnancy.. i feel silly to ring if it’s something little but i’m in a lot of pain and don’t know what to do. It sounds like i’m having contractions but i think to myself i’m only 21 weeks.

I’m just really worried☹️

Can anyone give me some advice please!! xx