is it necessary to start taking it on the first day of your period? What would happen if you started it about a week before your period?

The instructions should say to either start it on the first day of your period or the Sunday after your period starts.

If you start it on a time not suggested, you are at higher risk for spotting, and you have to use backup protection for a month.

A week before your period you have likely already ovulated so it is not going to protect you and you will most likely have your period, but it could actually be longer while you are on the pill. You need to use a backup method until after your period. While there are no real health risks, you may just be making your coming period a little more of a pain in the butt :) I would wait until after your period (or if you have taken a couple stop and wait) because the purpose of the pill is to prevent ovulation (which triggers your period a couple weeks later) and you are already past that point in your cycle.

Thanks guys. I think i might be patient and wait untill my period comes :)

So if i start my period before this sunday coming and i start taking the pill on sunday, will i be protected from then? Will i not ovulate after sunday?

It depends on the pill. The package insert should tell you when you can expect full protection. With some it's 7 days; with others, a full month.
Or you can ask your pharmacist. Probably best to use a backup protection for a full month to be sure.

Thanks. I've just read the leaflet and it says if i take it on the first day of my period, i will be protected straight away, or if i've alreay started my period, i can take it on day 5 of my period, but i won't be protected for 7 days.