I need to be informed of how this works!

Ok so last Sunday October 2nd, I began taking birth control pill. My period was suppose to come on October 5/6 and it hasn't come, and all I feel is tender breast. The day before I got the birth control I took a pregnancy test and it was negative. But the day before I took the birth control me and my boyfriend had sex and he pulled out and we've been using the pill out method for years and things were fine, so like I doubt I'm pregnant but like is this normal or should I be worried. I'm also feeling pain in my ovaries.