Basically, it was combination of many things that lead me to disbelief but firstly, it was the double standards I saw in my religious community and the inability to tolerate questioning and also too much division even though my religion's holy scripture claims that it is a clear book, and if it was from other than God, you would find a lot of disagreements.
And being an atheist has somehow gave me freedom and sadness like when I was in religion, I can do only limited amount of things and cannot be truly myself, I was always worried if me and my parents would end up being in hell or what if I lose my faith in God or what if I got punished in my grave, I am also bisexual so the part that it is sin made me cry and pray a lot to take this "abnormality" away from me, now I do not need to hate myself and my feelings and desires, I can be friends with anyone and can do a lot of things which I cannot do, I can question my views more boldly and look for unrestricted knowledge.
Sadness came though due to the fact that God, who was the source of comfort and fear for me, the source of ultimate truth, the only thing I can trust to, my dearest friend whom I can call upon anytime, to whom I can talk in my whispers, is dead. That death causes me pain. Although I sometimes invoke a different god from my religion but deep down I know they also don't exist and so it makes me sad. And also, it stripped me away from that main character vibe that I am part of some special group who have the word of God and ultimate truth, worthy of forgiveness. Now I am just a tiny part of a huge cosmos.