Is this the start of labor?

All last night I was having horrible lower back pain. It didn’t go away when switching positions. I managed to sleep through the night but I did get up 4-5 times to pee, my belly felt rock hard and uncomfortable. This morning I get woken up by the back pain again but I don’t feel any abdominal pain or tightening just this lower back pain. It feels like it’s coming on in waves but it’s so irregular I can’t even time them cause the intensity varies. I’m 38 weeks and got checked yesterday, I’m 1cm dilated