Stress or Pregnancy???

His d*ck touched and rubbed the outside of my vagina but didnt come in but not for too long. Im still virgin though. I think it didnt have precum but now im 10 days late and im afraid thay i may be pregnant and im getting paranoid because it never happened before. But on this month i reaally stressed myself out because we had a problem with our relationship and i was reaally really stressed! My friends tell me that is from stress but im scared because im only 15. What do u think? Am i pregnant or is just my cycle plus that i am REALLY stressed this month?