I am a Catholic and I believe in God. I believe in God because He has revealed Himself.
Now, let me point one fallacy in your words:
“I am an atheist because I am agnostic. There is no proof to back up any god out there”
Atheism and agnostism are two different cakes. Atheism is the belief that no god exists. Agnostism is the belief that, despite evidence for either side, a god’s existence cannot be proven nor disproven. I’m sure you already know that. An atheist cannot be an agonstic, nor can an agnostic be an atheist, because an atheist believes no god exists, while an agonst simply believes a god’s existence cannot be proven or disproven. If you were to believe no god exists simply because a god cannot be proven or disproven to exist, than you would also, by that same logic, have to believe nothing exists. An agnostic is indifferet to the evidence of whether a god exists or not. An agnostic, therefore, is indifferent to the questions on life, existence, love, truth - whether they exist or not is subjective, because the individual dose not believe they can be proven or disproven. Hence, the person dose not actually believe in anything. Atheism, on the other hand, uses evidence for its case. So you can see that agnostism and atheism are two different cakes.