Is there a God or heaven?

Often people are challenged to prove the existence of God or heaven.  I think a related challenge is to prove you truly exist.  The you I am referring to is that essence of you, your thoughts, your personality, your likes and dislikes.  There is a proof that I exists since "I think, therefore I am?" but to prove you exists is more difficult.

You may start by trying to prove that the coffee in my cup or my cup actually exist.  There are indications that it may exists.  I can taste and smell the coffee.  I can feel the heat and weight of the coffee.  

But, does Mickey Mouse actually exists?  I can see him and hear him. What about Minnie Mouse?  An amputee can often feel the limb that has been removed but does it exists?  I can often smell something that was near but is not there anymore. Does it exists where I smell it?

So we have indications through our senses that things or people may exists.  If these things are merely imaginary inputs into our conscience then something or someone must be providing theses inputs.  Could this be God?

Now, what about the essence that is you.  Are your internal thoughts part of your body?  Do your emotions originate in your blood pumper?  As you get old and lose your memories and mental capacity do you still exists?  If you have an essence that is you where does it go when your body quits?