Yes, there is a possibility for you to get oral HSV-2 if you don't use protection. The risk is higher if herpes lesions are visible.

I perform oral, I might have herpes 2 . Is it differn than my girl desease or same?

If she has genital herpes and you perform oral sex on her you can get oral herpes.

Yes it is possible. You can lessen your chances of getting it if your partner is on anti viral therapy but again this only lessens your chances it doesn't eliminate it. I suggest using plastic wrap during oral sex. You can also use dental dams but they can leave some areas on the vagina that emit the virus uncovered.