Can stress be a cause of my period to be longer than normal?

Certainly: Stress, lack of sleep, changes in diet or weight, prescription meds are just a few things that can alter your delicate hormone balance. This alteration can lead to a heavy, light, early, late, or skipped period. As long as the abnormal periods normalize in the next month or two, then nothing is wrong. Otherwise, if any other symptoms are present, see your doctor who can run some tests. GoodLuck