Period cramps just getting worse

Last night I went to bed around midnight having very light cramping. This morning I was woken up to more cramps around 4am that were a bit stronger. Drank lots of water, changed positions frequently, and keeping an empty bladder and even tried walking around a bit and nothing is helping and it’s getting worse. Still not unbearable but it’s in my back and lower abdomen. I’m almost 35 weeks and I’m trying to wait a few more hours for my dr office to open to call but I’m getting nervous I’m waiting too long since I’m still preterm. No bleeding or fluid leaks. Need advice on what to do... wait till my dr office opens or just head to the hospital???