Is this normal???

I’m almost 21 weeks pregnant and I’ve been having some crampy/achy feelings in my lower abdomen... some of the time it’s been on the sides of my abdomen... I’ve had round ligament pains before and it doesn’t feel anything like that... it’s just such an ache it’s about to make me sick!! I will hurt for about 2 hours then it will go away and now it’s back again.... Is this normal?