Ligament pain?

Friday evening and agin just now I got sharp shooting pain. Lasts a good 20-30 min. It's down below near where your hip/ appendix would be. And it only happens on my left side. I was scared it could be contractions (28 weeks with Di/Di twins). It so bad I'm in tears. Could it be just severe round ligament pain. Or maybe just my boy. I know he's on that side and his head is pretty far down over there. Don't know what to do!