My girlfriend claims to be d at a party?

she went to a party and wasnt planning on drinking. she doesn't drink that often so i took her word. later that night txting her she said she ahd 2 shots/ 2 beers. not bad. drinking games and such. she decided to stay the night which i was sceptical about becaus she would be sleeping in the same house as drunk guys. she said she was 'shooed' into a room w/ a guy and went to sleep in the bed. she says she doens't remember anything after that. at first she told me nothing happend but i had a sickning feeling that something did. she confessed she thinks she was d and told me her story. she said she woke up fully clothed but felt kinda weird down there as if she might have had or somones fingers found her if you know what i mean. i really dont know how to react. i mean she had her chance to leave with a sober driver but chose to stay. they were old high school friends which she umed she trusted. her 2 girlfriends who 'shooed' her into the room were suppose to be pretty good friends. im almost having a hard time believing she doesn't rememeber much because she said she only drank so much. she thinks she might have drank more but cant recall specifics. i've drank with her on several occasions and she has maintained herself very well. i just dont see her blacking out and waking up with some guy. she is pretty rational for the most part and i dont think she would act out like this. i would like to know who i should react and act twards her until i get to the bottom of this. and if ur wondering why i wasnt there im 2 hours away because of work. i almost feel like this is my fault because i wasn't there to protect her but at the same time i shouldn't have to baby sit her. the only other thing i can think of is that she was roofied or some type of date . idk can anyone give me some advise sorry for typos its yahoo and i feel lazy typing u know how it is all of you iinternet users.