Yeah, I went through that process. I realized I am just the result of a biological process, in essence much like bacteria in a petri dish.

There is really no separation between the mind and the body.

We still don't fully understand consciousness, but we know most of our decision are taken unconsciously well before the conscious mind is aware of it. There are a myriad of books about this, but this wikipedia article is a good introduction:

https://en.wikipedia.org/wiki/Neuroscience_of_free_will