Late period!! Am I preggers?!

Michelle • Sept 29. 1995. Happy in life and happy in love. Studying hard to build my foundation for the future. Open to talk 😊
I had unprotected sex with a guy I know since I was 12 on November 23. He didn't cum inside me, but I still went out to get the "Take Action" pill and used it with in the 72 hours time frame. 
On the first of December I had what looked like a period, it had the part of my liner in it and it was really light and it lasted 2 days. I wasn't scheduled to have my period until 22 days after my last one which was on November 19th. On the take action box it said my period ahould show up on normal schedule, but it late. 
I now started to notice a change in my body. My breast have gotten bigger and they have a bit sore lately but that's something that happens when they grow and when I'm about to start my period soon. My weight also went up a little, but I believe that's because of lack of excerise and eating out a lot more. 
I'm really worried if I am pregnant because I'm only 19 and I'm in school and have a job now, and a child isn't want I was expecting at all. 
Help I need some advice please...