I'm 5 days late on period bad back pain and had diarrhea yesterday and just feel sick. had a pap done last week with abnormal cells.

My first thought: is that you have more than one thing going on. I believe you, unfortunately, have become ill with a viral gastroenteritis just at the time of your expected menses. This often results in worsening of usual period symptoms as well as the symptoms of the coexisting disease which could also delay your period. I would not worry that this has anything to do with your abnormal Pap smear or cancer.