[firstly i hope this is the right place to right this and secondly i am not very good at english]

ok so i am a teenager and i have recently found a girlfriend and i have been having weird fantasies about her having an orgy with some people and it makes me seek to the point where i want to puke. So what i want to ask is is it normal to think of stuff like that?Do i need help?Does she have fantasies like that too i hope someone helps me cause i cant take this anymore i am getting sick of this i just want it to end please......