Question?

So tonight when I stood up, ( wasn't a sudden movement or anything) my stomach completely hardened and I couldn't move or barely talk. I literally waited it out. When I lay down it doesn't hurt as much but still is uncomfortable . I don't know what exactly this is. I know it's not Braxton hicks and feels weird for real contraction too, but I can't really say. Not the first time it's happened but also doesn't happen regularly. Any suggestions or ideas on what it could be? Or what's happening?