Menstrual cramps?

Woke up at 230am last night and had on and off period like cramps until about 415am. My contraction timer said they were about every 6 minutes or so and lasting about a minute each. They stopped around 430ish when I was able to fall back asleep. 35 weeks and 2 days pregnant. Is this BH? Or body preparing for contractions? 2nd pregnancy but my water broke with my first at 36+5 and I never had BH so I'm unsure how labor starts without water breaking. Any one experience this?