Am I going crazy?

I would suggest talking to someone about this that will be able to help you figure out why you have resorted to this.
If it helps you feel more normal, I develop little crushes on fictional characters sometimes as well. I mean they don't really get extreme, but it happens.
There's probably some underlying event or issue that is tied to this. So talking to a professional is the best advice I have for you.
But no, you're not crazy.

...is she hot?

I completely understand actually. I'm always going through periods of obsession with fictional characters, some lasting more than others. Without fail though, they tend to subside on their own. They come back sometimes when something new comes out with the character (new season of a show, or a sequel to a movie or a video game) but regardless of how in love I am at the time, they always hold a special place in my heart.These obsessions become problems though when they start to keep you from functioning normally. First (like Gail and Suzanne said) try to identify some kind of underlying issues in your life that could be causing your love of this character to be so extreme. Also, it can be beneficial to channel an obsession into something creative. Keep a journal, make art, write a story; all of those things can help keep it under control.

Have you ever thought that maybe somewhere in the real life there is a version of her waiting for you?

I completely understand how you feel. I am basically in love with people that either don't exist or don't know I exist ( boyband members ha ) I think and fantasize about them all the time and in the beginning, I was wondering the same things as you: Was this obsession healthy? But I have come to realize that as long as it's not hurting anyone, it's completely fine! It's actually great to have someone, even a fictional person, that you can rely on and will always be there because sometimes the thought of that person can make you feel better if you're going through a hard time. So yeah, rock on!

I think it's totally normal for teenagers and even young adults to be obsessed with fictional characters. They are much more easy to love than real people. Perhaps you can try to focus on other things more often - not cut her out of your life, but just try to lessen the time you're thinking about her. Try to find things to do that you're interested in, but that involve a lot of concentration on your part so your mind can't wander back to her. That will at least give you a little while of thinking about something else without saying farewell to her for good. I've got lots of fictional characters I love, and I'd be heartbroken to decide I could never think about them again.

Well I guess it's time to chew some nicotine because this clearly isn't healthy. If you treat this ass a relationship, you are going to have to break up with this girl and not talk to her for a while until your mind is in the right state to function. You cannot mess your grades and life up for anyone. You are hurting your future thinking about this girl. That isn't worth it. It's time to ween yourself off.