It sounds like you went through an ego death. That's part of what can be so healing about psychedelics, although it can also be really scary. I heard one scientist describe it as a reduction in functioning of the "dominant neural network," which allows the other parts of the brain to communicate more freely and create new ways of functioning. People say the best thing to do is go with it and not fight, but that's easier said than done.

I experienced something like it briefly on DMT -- a complete forgetting of myself, where I was, and what I was doing. It felt like drowning, in a way, like I kept slipping under the water of forgetfulness and had to forcefully pull myself out of it.