This is PMS syndrome type of thing, which is called as Pre-mensural Syndrome. Some female have some sort of problem and severity varies greatly before the start of their menses. But since you have mentioned that you are having problem one week before your period, than I am not sure wether it is really PMS or some thing else.
As far as PCOD
is concern, it is not going to produce this type of problem and it can alter the period.
I would suggest you to consult some gynaecologist and if possible to some psychologist
also to make sure that this is not PMS. In the meantime try to maintain your proper diet and try to include some sort of excercise in your routine.
Thanks and take care