First of all if your to have sex always use potection because some many things can happen like getting pregnant or getting a STD. I know what your feeling because i am 16 years old and i myself think that i could be pregnant because i also did the same but was your period normal or was it not so normal? if your spotting i would say that you should get a home pregnancy test just to be sure. was this guy your boyfirend? ......if yes....... how long have you been with him?