Random contractions?

This has happened 3 times now, but basically I’ll just be perfectly normal, and all the sudden I’ll get a full on contraction, it’s just one contraction, lasts like 20-40 seconds, and then that’s it. I had two a few days apart a couple of weeks ago and then just today I had it happen again. And I know for sure it’s not Braxton Hicks, I get those all the time 🤦‍♀️ like it feels like a real full force contraction. I’m 34 weeks, is this normal?? I never had it with my first