I have forgotten how to live The previous years of my life feels like a dream. I was happily living, consumed with studies, learning things, watching youtube and stuff, enjoying a lot, mind was busy in various entertaining stuffs. But, I don't know how it started, but all those passions are waning. Its almost as if I've forgotten how to live. Live as in the previous ways of my living. I am now trying to find a way to live as I've lived in the past but can't seem to go back to the old ways. I mean I want to find something fun for my mind as I had in the past but I just cant bring up enough passion.

What is happening to me ?
I cannot of course say what is happening with you. But here is a thought, since you have used the tag of impermanence for this question (and quite correctly, I think). 

Our minds are addicted to sensations- craving of pleasurable sensations and aversion to painful sensations. The addiction is to react, depending on which type of sensation one is experienceing, which changes from time to time (hence the impermanence in the subtlest form). An addicted mind, like an addict, grows accustomed to a high- once staisfied with one drug (here 'fun'), it wants another. Addict wants a high and once that is satisfied, it will want another high. This wanting of high (craving) is a conditioned pattern of mind, at the deepest level- conditioned because of our ignorance to the impermanent nature of phenomenon. 

What you thought of as fun, is now boring. But the mind is addicted to 'fun'. So now it is in a bad mood since it can't find something new, a new fun thing to do. Don't get me wrong, having fun is important. The obsession is harmful- we loose the balance of mind.