Does anyone have any advice?

ok, heres the thing. me and my girlfriend had . we used protection and a spermicidal lubricant. the condom didnt break or anything like that. we had like a month ago. shes been having the feeling she will pms for a while now. her feeling has been the same for a few days. she hasnt shown any symptoms of being pregnant or anything like that. her periods are random and shes kinda freaking out that she hasnt pmsed yet. is it the stressing thats doing this?? are we being over paranoid?? and does anyone have any advice?? PLEASE HELP