Just wondering if anyone's labour started this way??

Each day I am getting more and more period pain, and today it was constant allllll day, with only a 2 hour break.
It didn't matter if I was sitting or standing etc....it was still constant, no real breaks, but occasional spasms where it got even worse? This has never happened with DD or DS, and I was induced both times then, so not sure if this might be the very beginnings of spontaneous labour/pre-labour? It has just thrown me cos it was constant.