God is in the now. Guilt/shame, resentment, and fear, in all their forms, are departures from the now.
What I do:
I come back to the now, gently but persistently, and turn my attention to the task at hand.
If necessary, I ask myself, 'is anything bad happening right now?' It almost never is.
I can ask myself what my physical senses are telling me right now.
I can distance myself from my thinking by prefacing any thought I'm in the middle of having with 'My mind is having the thought that ...', so that I realise that the junk-spewer is simply spewing junk, nothing more.
This works, and that's how God is found, in my experience.