Side cramping...

I started getting cramps on one side of my belly tonight.. Enough to cause me to lie down. It's been about 15 minutes now. I am wondering whether it's dehydration (worked a long day today) round ligament pain (expanding uterus) or gastrointestinal.... It's so hard not knowing what your body is telling you. Drinking water now but just curious if anyone has experienced this around 17 weeks.