Sounds like a great experience. The mushrooms are in my opinion definitely one of the best psychedelic plants for humanity. 
I have experienced them many times. The anxiety you felt was most likely produced by the fear of letting go. This is also something that can make the stomach feel worse. In my experience one needs to use the plants to find the pathways but the real work is to learn to walk the path on your own. I would guess the images you saw may have been teaching techniques for doing just that.
These plants have the ability to clear the way and teach one to see beyond our limited perspectives.
The view they share with you is only a preview.