I've been getting this also. I am 40+5 and really thought it was happening. Pretty strong contractions every 12-15 mins apart for the entire night, although managed to sleep ok on and off. Woke up early but decided for the first time in ages that I was gonna laze in bed. DH got home from his night shift and we had breakfast in bed - contractions continued. Got up had a shower and dressed and within half an hour they stopped! Had very small erratic contractions for a few hours and now seem to have started with the strong ones again!
No idea what is happening! Just praying it means it will start in the next day or so!