I tend to get my strongest BH from about 9pm throughout the night, some strong enough to wake me but they don't turn into anything, but it all adds to the preparation!
When I was overdue with my 2nd DS and had a couple of false starts, a midwife put it much better, that with early labour its like trying to start a temperamental car, it ticks over so many times before something 'catches'! And off you go!
I think its exciting that you are noticing changes in your body, albeit a runny tummy is not something we would ordinarily welcome! It will be interesting to see what (and when) things do start for us, and if it was a sign of things starting!
Glad to hear your mum is helping you out, hopefully you will be able to get some sleep this afternoon, its a full moon on Friday, apparently that sets a sudden rush of labouring women, not sure how true that is! 
In the meantime, I am going to potter, relax, eat, and enjoy as long as is left of what is my last (sob) pregnancy.