In my early 20s I contemplated the existence of God. The books "Atheism: The Case Against God", by George H. Smith, and "An Atheist's Values", by Richard Robinson, persuaded me that God does not exist.
Just looking at the titles of the books it would seem that you where not really contemplating but rather looking for people that gave you arguments you wanted to hear. Im not saying that I disagree with you, and I havent read the books so I could be completely wrong, the books may present the counter arguments too.
The books are philosophical works that do consider counter-arguments.