How come I think I have a girlfriend when it is just me dressed up as a girl ?

I keep on refering the girl version of me as my girlfriend and I don't know why. Everytime when I dress up as a girl it makes me feel like I have a girlfriend. I had a hard time finding a girlfriend and whenever i dress up I feel that is my girlfriend. I even created another facebook and putted I'm in a relationship with the girl version of me. I'm a Straight guy and I do not understand this.