Possible labour? Please!

I'm 3 days overdue, had a sweep today, almost 3cm dialated, pretty much fully effaced and waters ready to pop. had the bloody show and constant cramps pretty much straight after.

It's been about 4 and a half hours now, decided to get on my ball and the constant cramping had died down but I've been cramping every 4-6 minutes so pretty convinced it's contractions now. I decided to stand up and do some things, kill time and now my cramps will be like non existent until I sit on my ball again and then it goes back into pattern

I also feel like I really need to pee when I cramp but I don't actually need to pee.

Any suggestions as to what's going on?