It sounds to me like you're burned out.

Have you been dealing with any stress?

Well, take this however you want but I feel like I need to have it said:

I can say that I recognize that feeling and many experience it. It's often combined with filling your heart, AKA time, with too much of something. Many say that it's simply about stress, though I believe that that it could be the same with things as gaming, facebooking, music etc. You know, things that doesn't really stress you up. Many people would solve it by doing something else for some time, like a vacation and such. My thought is that those things doesn't actually fill the emptiness, they just suppress it for some time to then let them back with stronger force next time.

So to solve this issue. Here comes the part that I mentioned that you will have to elaborate with yourself and not take it as I want to hammer something into your brain. What worked for me was when I became a christian, it filled the emptiness I had in me and made me a better person in general. People I previously couldn't stand changed in my eyes and I could feel compassion on a new level. I'm still an extremely flawed and incomplete human being but what have changed is my will to change to the better. I tended to think that I was a lost case.

Now I know that it is extremely taboo to mention these things but I couldn't help to do so because I can apply your current situation on my own experiences. My advice to you is to see what you fill your life with and how it affects you. I also want to say that you can send a PM my way if you feel like talking to someone who has been in the same situation.

Also, the solution could be something as simple as drinking a glass of water. One tend to demand something that one not truly can put words on when the body wants water.