Stretching or contractions? 22 weeks pregnant?

This evening I started noticing menstrual like cramps, mostly around the middle to left side of my lower abdomen. Its not excessive pain or bleeding or changes in discharge, just feel like time of the month cramps. The past two days I've experienced several hot flashes as well, so maybe cramps could be hormone related? Been doing a lot of garden work, bending over, etc, maybe this could be the cause?