Dude, all I can say is find a hobby and a woman. Then "Follow your bliss" --Joseph Campbell
I am sure there are tons of things you want to do in life, so figure them out, figure out how to do them, and then do it. Very simple
The reason you have no interest in life is probably because you are not doing anything, just sitting around and waiting for "life" to bring you the joy. You need to be active not passive.