Hi.me And My Gf Had Some Close Moments At The

hi.me and my gf had some close moments at the start of this month.we didn't had any penetration.only my penis touched her vaginal opening once.may be some precum was there.it happened on november 4th.it was after 3/4days of ending her last period.is there any possibilty of pregnency here?? she donot have any breast swelling,vomiting, spotting,frequent urination.bt she's having gastric problem,mild cramping,tiredness etc.she's also expecting period.but it is not coming though.is there any possibity of pregnancy???and if there any how we can stop that??