hopes and depravation

i realized a long time ago that i feel like i can't ever be one hundred percent happy. My reasons are legit, though, for one, i know that every good thing ends up having an end
    -but is that reason to not enjoy the present? It'll make youappreciate what you have even more
And when that end comes its like a big, sinking feeling. A starving feeling. The worst feeling-sadness is not the opposite of happiness. This, what i am talking to You about, is.
That's just one reason. The other one is more psychological-i'm to stuck in the past to fully enjoy the present.

When good things come around i'm so certain that it's not going to last or that it's not going to happen or that hesheit will stop liking me or never liked me in the first place or it's all just a joke or i really didn't win first place it was just a mistake or oops no one ever really liked you we just felt bad for you.
my worst nightmare is
      -no its not you just realized that it is
that everything good i have in my life will suddenly go away. That every good thing in my life was just a facade.
That nothing is real.
i'm afraid that nothing is real.