This clock it ticks, my mind it stings

I can't seem to get anything done these days. I have seem to become the biggest procrastinator. Some days I just sit there and think about things for hours. I try watch TV and I'm still thinking. I'm thinking about what I want to achieve and accomplish and that I want to go out there and do these things now before it's too late. I'm thinking about moments that have passed that are never to return and how I miss them. I'm contemplating whether I only miss them because they are gone and if I were to have them back would I even want them in my life? Stupid relentless questions and thoughts racing inside my mind. I can't concentrate on ANYTHING these days without my mind wandering. I feel insane. There is one thing that is keeping me grounded but I don't want to put much thought into it just yet, although I do need something to bring me into this very moment away from the past and the unknown.