I had believed in God for 60 years. For the next 10 years I reverted to believing it was some kind of deistic god or higher power, but most certainly this higher power was NOT the Christian pagan god, Yahweh (Yahweh in case you didn't know was a minor Canaanite god in a collection of Canaanite gods that included Asherah, Baal and headed by chief god, El. The early Hebrews living among the Canaanites picked up Yahweh and made him their chief god). Recently I've decided to just go full atheist. I've never had any proof God exists; I've never had any prayers answered; the world is cruel unjust place filled with violence and death; the Bible is riddled with errors and inaccuracies; there's no proof a Jesus of Nazareth ever existed. It just makes more sense to me that it was natural selection that created this marvelous universe. We are a tremendously complex accident and we are now destroying the earth with our avarice. In 100 years global warming will have killed off most of the earth's population and rendered everything but the north and south poles uninhabitable.
What convinced you God exists or doesn't exist?
I guess you mean that God did not convince you that He exists. I do not believe that God ever convinces anyone of His existence but rather people become convinced by doing their own investigation. I do not think God wants to provide absolute proof of His existence because that would be too easy, and God does not make things easy.
To be brief, I was not raised in any religion or believing in God. My parents had been raised as Christians but they left the Church before us children were born.
So I never even thought about God until I stumbled upon my religion, the Baha'i Faith, during my first year of college. Shortly after that I became a Baha'i and I have been a Baha'i now for over 51 years. But probably because I was not raised believing in God I never had a close relationship with God. In fact, it has been very difficult for me to believe that God is loving or just because of all the suffering in the world. As for God intervening when we say prayers I cannot say I believe that either; although sometimes I think God is guiding me in some way, I can't say "I know."
Just recently in a conversation on this forum I realized that maybe I am a theist-deist.
All that said, my religion is similar to Christianity in that we believe God is a personal God, but not as personal as the Christian God. This website explains that.
God in the Baháʼí Faith
Back to why I believe in God. I believe in God because of the Messengers of God, who I believe are evidence of God's existence. I believe there have been many Prophets sent by God, but only a handful of universal Manifestations of God, like Jesus and Baha'u'llah.
Question: How many kinds of divine Prophets are there?
Answer: There are three kinds of divine Prophets. One kind are the universal Manifestations, which are even as the sun. Through Their advent the world of existence is renewed, a new cycle is inaugurated, a new religion is revealed, souls are quickened to a new life, and East and West are flooded with light. These Souls are the universal Manifestations of God and have been sent forth to the entire world and the generality of mankind.
Another kind of Prophets are followers and promulgators, not leaders and law-givers, but they are nonetheless the recipients of the hidden inspirations of God. Yet another kind are Prophets Whose prophethood has been limited to a particular locality. But the universal Manifestations are all-encompassing: They are like the root, and all others are as the branches; they are like the sun, and all others are as the moon and the stars.
Twelve table talks given by ‘Abdu’l-Bahá in ‘Akká
The Three Kinds of Prophets