Rough Night, looking for advice

I'm 35+3. I woke up last night around 11 feeling not good at all (nauseous, crampy, back pain). I got up to try to use the bathroom and went to recline on the couch for a bit.

I started timing contractions because I realized I was having them (this is my second pregnancy). I had consistent contractions from 11:18pm until about 2am. They actually got quite intense around midnight, then eased a little. They were never longer than 50 seconds and were 2 minutes apart. At 2am, they started getting further apart.

I went to lay down again and fell asleep until about 6am. I woke up feeling crampy and exhausted but I have not felt a "contraction" again today.

What do you think happened? Prodromal labor?

They were definitely contractions and not Braxton hicks. They felt exactly as they did in my labor with my first.