If they are lasting longer than 30seconds, and you are having more than one an hour, I would go to the hospital for
monitoring. Especially if you have a history of preterm
labor. At this point there are more options for controlling preterm labor, than of your contractions continue and your water breaks.
In the meantime, drink lots of water. Dehydration can cause contractions. Empty your bladder frequently, and most of all, take it easy. Lay down as much as possible.