Hiya AndiE!
Firstly, Congrats & Good luck with the impending arrival of bub...

Secondly... i don't know how muhc i can help answer your question as i 'felt' like i was in pre-labour for weeks.

I had the period type cramps, the lower back pain, the pinching pains when bub would grind my cervix... and everytime i even hoped it was a sign it just made the time drag on for longer!

The two days before i did go into labour though, i had a lot of increased 'pressure' or weight in my upper thighs. There were occasions when it was increasingly painful to walk or have weight on my feet at all. I also had really stingy, sort of itchy nipples. Maybe all the scratching and pulling at them is what actually got labout to start, who knows!

Hopefully the time comes for you soon, looking forward to seeing a birth announcement soon!

ETA - As for early labour... the cramps were more like a wave of pain. Instead of being consistent, they were consistent, with a peak... and even the slightest i could tell.

Three people got in before me while i was writing this, lol!