Cramps or labor

Been having moderately intense what feels like menstrual cramps this morning, intensity coming and going but kind of a dull ache that is consistent. Last time I called my dr about something like this they said it might be preterm labor so I went to l&d and wasted the day there because it was nothing. But people say early labor feels like bad cramps? I'm obviously a first time mom. I'm 36 and some change right now