I have my period and i usually get nauseous sometimes lightheaded and diarrhea what can i do to help these symptoms?

Pelvic stability : Lightheadedness, diarrhea, & nauseousness at menses suggests autonomic nervous system hyperactivity. My own idiosyncratic theory is parasympathetic excitation aroused by pelvic girdle instability secondary to relaxin hormone secretion; cause of loose pelvic girdle joints. Near-term, try spanx or sacroiliac joint belt. For long term yoga might increase stability & pelvic muscle tone; hopefully.