if you were 30 weeks, having 'normal braxton hicks' for about a month
but a few days ago you started vomitting, then moved onto having a runny tummy and for about 4 days you had been having really bad stomach cramps and BHs all the time.
Ones that made you wince?
With DD i was in similar situation except I KNEW i was dehydrated as i couldn't keep water down,
i am drinking water fine this time and so don't feel im dehydrated at all, and am worried they will want me to stay overnigt on a drip again even though I am perfectly capable of keeping myself moist 
Part of me thinks its just a tummy bug - get on with it.
But the fact im 30 weeks and the bug is causing very strong BHs makes me think i should just maybe tell them (but whyy?!)