I would say that maybe when you are crying and you bend over and are using your abdominal muscles to cry as well as stand back up, you may ( like AnnieBrooke said) be giving yourself some sort of muscle spasm or even pinching a nerve when that happens. Due to the muscle spasm or pinched nerve, that could be giving you the pain (menstral cramping pain) that you had for the rest of the day.
Well, one idea is to stop bending over when you are crying. It kind of sounds like you are giving yourself a charleyhorse or muscle spasm in that position.