Religion

Recently, I had a talk about religion with one of my friends from America. He is religious. He asked me if I believed in God. And then I was really worried about how he'd think of me if I had said like "I dont believe in God. "And I said like that . But he didn't look at me like the way I thought he would. It seemed like to me that he just wondered why I thought like that. And I couldn't answer to the question. Cos I'd never thought about it seriously . It was a really awkward situation.I was at lost for words. How would you guys answer to the question?