Missed period on birth control?

This past week I was supposed to get my period as I had just finished my pack of birth control, but I hardly even spotted. I’m not exactly worried I’m pregnant but I took a test and it turned up negative. I’ve never missed a period and I’m just confused as to why it skipped completely. The last time I had sex was about a month ago, but I don’t think he even finished and we used protection plus I’m on the pill. I don’t take my pill at exactly the same time everyday but I always take it in the morning. I have been stressed lately and my sleep schedule was off the week before I was supposed to get my period but it’s nothing I haven’t experienced before, so I’m wondering why I didn’t get a period this time. I haven’t changed my eating or workout habits and i haven’t started any new medication or switched birth controls recently either. Any insight? Advice? Should I be worried, take another pregnancy test, or maybe go to the doctor?