I wonder how can you know who God is? or if he is?

My therapist is really into this quantum physics spirituality (my own words to describe it), but its very interesting and appealing in ways.

I grew up Christian though. Hard core - Trinity believers who would have none of the stuff my T believes in.

Then there is agnostics who believe in no God.

How can I really know? Inside honestly, i feel like its all man's way of explaining its existance, its pain, and to bring hope for himself. Thats where i've been in the last 6 months. Because my beliefs are all over the place, I know at some point ive been wrong and it all confuses me. I always feel like God is mad at me. Why can't i figure out who he is? I pray all the time for him to speak to me (yes i know he speaks in quiet whispers or so i've grown up being told). I'm really struggling with this one.