Don't think changing your avatar will make you safe. I'll eat baby lobsters. I'm not above that.
I find that meth, while very effective, can last anywhere from 20-24 hours...much too long for for my needs. The crash is also very harsh and would probably make it difficult to attend class the next day..I would compare it to coming down from a 2 day crack binge, though each individual drug obviously has its respective quirks.