Contractions randomly?

I get a strong contraction out of no where.. then I think I’ll get another one and it never comes. Sometimes I’ll get them 10-15 min apart but only 3 when it happens and then it stops. Sometimes I’ll get one really good one and then it’ll take a while to get a small one here and there. I’m 39 weeks and I’m goin crazy thinking they’re going to stay constantly and they don’t.

Is this normal?