Only two things can reveal life's great secrets: suffering and love.
Listen to your heart beating, follow the thoughts you can't control, control your desire to get up at once and to do something useful. Sit for a few minutes each day, doing nothing, getting as much as you can out of that time.
Apathy. I haven't yet reached that stage. I'm still at the complaining one, but I imagine that soon—in a matter of months, days, or hours—a complete lack of interest will set in that will be very hard to dispel.
I'll just say that insanity is the inability to communicate your ideas. It's as if you were in a foreign country, able to see and understand everything that's going on around you but incapable of explaining what you need to know or of being helped, because you don't understand the language they speak there.