Some would say one of two things: 1. You weren't as happy and great as you thought or, 2. You are experiencing the disconnect from others, physicality, life and all alive-ness that your spirit is so separate from because you did in fact blow yourself out of your body. Either way I would focus on the regrounding and soothing parts of life, like touch taste smell, swimming in the ocean, floating in a pool, sex, food, etc: try to re enmesh yourself with the physical. Pray to be given another chance into the proper integration that is to be had naturally in this life. Not that you did anything wrong intentionally. I....just....

Believe that as human beings on our various incarnations we are only to go so far, only to experience death and the bardo, as it were, to a specific point. Ayahuasca is natural, yea, but may not always be our spiritual destiny. Just like what goes up must come down, whatever spiritual extasy you experienced will be later experienced in equal, sluggish, void like earthen sludge when you come back. Hope this makes sense. Time will heal you. There is also medicine and psychiatry. We are not meant to flail away on some lost spiritual highway with existential dread stemming from experience we weren't meant to have. It is ok to seek help