Hi, I Had Unprotected Sex For Only About 45 Seconds

Hi, I had unprotected sex for only about 45 seconds with no ejaculation then he put on a condom after those 45 seconds. I was still very worried about getting pregnant because it was my first time so 2 days later I took the Plan B Pill. Then 5 days later on December 6th I started bleeding. My period wasn't supposed to come until around December 17th/18th. The bleeding seemed light at first but then acted as my normal Menstrual Cycle heavy for 5 days. On the 5th day I was pretty much done bleeding so that night I had unprotected sex again for less than a minute with no ejaculation, just messing around. I would just like some clarification on when my next period is supposed to come since it came early. I'm almost positive it came early because of the side effects of plan B. & Yes I have learned my lesson about sex and know not continue until I'm old enough to deal with the consequences. But when should my next period arrive? Should I be worrying?