Sometimes you go through days where you feel like the happiest person in the world and you just can't find much wrong with your life right now. Sometimes though, you go through days where you feel like you're in this black hole. Everything outside may be great. The sun may be shining, your friends may be there for you.... but on the inside, you just feel like there's this vast emptiness and that nothing can ever fill it up. You become indifferent to what's going on in the world around you.
Of course you realise that this is just temporary and that one day everything will work out fine. You just wonder when.