Menstrual like cramps in late pregnancy

I'm 34 weeks and am beginning to feel occasional cramping that feels like menstrual cramping. Last night it was so intense it woke me up and was spread from my abdomen to my back. I was even breathing through it. Not sure if it was getting up and walking or emptying my bladder that helped but they seemed to subside a little after getting up to go to the bathroom. Is this "practice contractions"?