Stomach sickness

I got my period on Friday evening. My periods are very irregular (35-45 days lasting about three days, very light). But the past week or so I have been sick to my stomach, diarrhea, nausea. I'm not sure why I would feel this way but wanted to see if anyone else may have experienced this around their period?... I was beginning to think I was pregnant..: period came at 47 days though :/