birth control pill. please help!

I have been on the pill for seven days now. My doctor said I could startit at a random time in my cycle because my periods are so irregular. I was wondering if because I didn't start right after my period I wouldn't be protected from pregnancy within the first week? Or am I not protected until after my cycle and I have my period? The box says I am protected after seven days but I wasn't sure if it was different for me since I didn't start right after a period? I want to be sure I'm protected before I have sex (which is still going to be with condom).