I laughed while reading this. Religion is something people invented because they can’t handle the mortality of people; by religion, we make ourselves immortal. To believe in God and not ever doubt it, indicates a lack of education or a lack of brain. Your dad is right: you are too smart, too smart to believe in God. Be open minded but not so much that your brain falls out.
My first advice for you is to get in touch with other ideas, try to watch these videos:

https://www.youtube.com/watch?v=eo2LHKRR8NQ
My second advice: don’t believe anyone but yourself, so don’t even listen to me if you don’t want to. Believe what you want to believe, or just believe nothing. I’m not an atheïst, because I can’t prove that God doesn’t exist. I’m neither a buddhist or a christian or whatever. I am a person, just like you, and I don’t like to be put into a box. I believe in this life, and that we can make the most of it.
I’m really sorry if I offended anyone with this post, I really respect whatever religion people have.