Having taken many psychadelic drugs, I can sympathize with the OP. I have had some experiences where I undeniably could see "God". Many people have not had this realization, and many who have would object to calling it "God".
I think most religious debate gets caught up on the word "God", well I think you can also call it something like "the universe", "atman", "the self", "the laws of nature", "the dao" etc. People hear "God" and they think of the king-like, humanoid God of Abraham.
I guess what I'm saying is people who believe in God, and people who don't have different conceptions in their head of what "God" means. I hold the view that there does exist such a "spiritual experience" and many people (Christians, Buddhists, Muslims, and Atheists alike) have had this experience. You can also see common themes throughout different religions that point to this same experience.
It's hard to talk about this without sounding like some new-age hippie, but people who have had this experience will know what I'm referring to. It's not really something you can put words to.