Why did i faint?

i was talking to my friend at work who is a nurse and she was telling me a kinda gory story from work about a man bleeding. the next thing i know i am all dizzy, think i am going to be sick and before i know it i am on the floor with people round me. i didnt feel too good all day any way. do u think it was her story that made me faint or just coz i wasnt feeling too good. im having a bit of a hard time at the moment, cud that have contributed?