Is it normal I want sex so bad?

I'm glad that you have sought out some help for yourself. I think you should take it upon yourself to stay away from this unfortunate person. If you ever do end up forcing yourself upon this poor woman against her will then I hope that you are caught, and made to face justice.

If you truly want to get better the first thing you should do is to stop gratifying yourself to thoughts of this woman. You need to stop all masturbation, and completely refrain from fantasizing about this person. When you catch yourself fantasizing about her you to challenge your thoughts, and then redirect your thoughts to something else that is entirely different, and completely nonsexual.