When After Consumption Of Cileste Is One Protected From Pregnancy?

I started taking Cileste contraceptive pill this afternoon so that I'm not on my period whilst I'm away on holiday. My period was due in about 2 days. Just out of curiosity, how long must I wait before I am protected against pregancy? The leaflet says that if I start taking it when it's more than 5 days after day 1 of my last period, then additional contraception should be used until my next period. However, further research is telling me that I'm protected after one week. Can someone please tell me a straight answer?
Thank you!