frazzled - To feel completely exhausted and worn out, and unable to think straight, after a great deal of mental or physical effort
After being up two nights in a row writing a 60 page history paper, and drinking 60 cups of coffee, Simon's mind felt frazzled.
scheme - A large-scale systematic plan or arrangement for attaining some particular object or putting a particular idea into effect, often through deceptive means
It's better to be honest and work hard, and not spend too much time devising or falling for schemes that are tempting shortcuts to making money.