hmm...I don't know what to say..your period sounds very much like mine was...I never knew when it was coming. it just came once a month but it wasn't consistent like those people who knew they were having it every twenty eight days. I never had cramps or anything like that to know it was coming and it too lasted about a week. but it never went over that. I know stress will do weird things to your period. have you an obgyn you can call? or is there a planned parenthood or womans clinic you can contact? they would be the best people to answer your question.