Id call them. I learnt the hard way last time what happens when u hesitate to call them (go into labour and by the time u get to hospital your contractions are 1 min apart lasting about 1 min was not fun). Im not saying u are in labour or anything cos Im not an expert at all but the day before I went into labour (which im guessing I was actually in labour but just ignoring it) I was feeling really off with all sorts of weird and wonderful pains but I didnt even mention to my husband cos I thought I was just going to be a pain and didnt want to alarm anyone especially if it was false labour. I figure the people at your hospital and definitely your OB are paid enough so lets make them work for our money hehehehehe.

Good luck.