So recently I had asked a coworker about some pain I've been having on the sides of my breast and she had said that it had only happened to her when she was pregnant and said that I couldn't be pregnant but I had also had unprotected sex a little over a week ago. So I told my best friend who is 3months pregnant I believe and she told me I was because "pregnant woman can tell when other woman are pregnant", so now I am kind of worried since I am 17 still and don't know if I'm ready for that kind of responability. 
Can someone please give me their opinion on this?