What a horrible thing for you - brings back some hideous memories of my teenage years.
First, the reason they pick on you (especially about Astro Boy) is most likely because you are unique and independent and thoroughly enjoying yourself. People in general (and teenaged people in particular) tend to discriminate against others who don't "blend in."
You do something different - and actually, that's to be admired, not made fun of. I don't blame you for feeling so angry and hurt, but my suggestion is to turn this into an "Astro moment" for yourself!
Okay, so what would

do in this situation?

1. Realize this isn't about
you - but THEM. You wouldn't do this to anybody, right? Right! So look at these people as immature, insecure and destructive, and proudly hold yourself above it!!

2. Work with the school authorities to find out who did this, and have them (at least) compensate you for the cost of the destroyed book and anything else they damaged.

3. Check to see what the school's policy is on the loss/destruction of personal items. For insurance purposes, they might not protect anything other than they own books and furniture. That means you need to consider whether or not you ever bring ANYTHING into the building other than what you wouldn't miss if it were lost or destroyed. Not fun, but it IS the "real world."

4. Focus on the positive people and things in your life to get past these hurtful things. We're all here for ya, and someday you'll get that book back, I'll bet.
Feel better!!