Is it possible to have a period a week after your last period ended when i have always had regular periods? if so will it throw off my ovulation?

Irregular bleeding.: It could be due to infection or trauma to cervix and vagina or hormonal problem at your age. See your Gyn, I hope this helps.

Already off: Most women will occasionally have some menstrual irregularity. It may be stress or maybe something else. Since it's ovulation that controls the periods, I suspect that your ovulation got thrown off, and that's why you're having the bleeding. I would give it some time to see whether your periods become regular again.