Just a whole lot of emptiness

How is it possible for my mind to be so damn busy and racing yet be so empty and vast at the same time?
Now, to match the thoughts with my emotions? What if it's my emotions driving my thoughts? Can it work that way?
Alot of the time, my head just starts going out on a tangent and I have no control of it. The thoughts? Does it make sense to say that a majority of the time I don't even know what I'm thinking? Can it be just a constant noise tunnel that is never ending? And sometimes, very rarely, I can actually grab one of those thoughts and know what it's saying??
Sometimes, they aren't so nice- and I don't think this is the place to say them. Other times, its that I'm just so tired and my head is telling me to stop and listen to myself, listen to my body and relax.  And alot of the time, the thoughts are that fast, I have no idea what is going on..
I have so many questions, so many things I don't understand.
It's all very overwhelming...