I am a 17 year old, and I have a question about my period being 4 days later than the 28 days. I have skipped my medications (depakote and abilify) two nights, and have been using illicit drugs and have recently quit the illicit drugs. (cocaine mainly.) I also have been recovered from an eating disorder but have been purging off and on recently. maybe four or five times this month. Alongside this, I have been stressed (I have a canker sore in my mouth and a knot in the back of my neck , but I don t know if this is a legitimate amount of stress to have missed a period.) Could all of this put together likely cause a late period?