DMT is supposedly a chemical hallucination that is released in your brain as you are dying. This is why some people that have died and returned, have claim to have flash-backs, or near death experiences.
What could this mean? We are already dead (or dying) and what we are experiencing now is a flashback induced by the DMT, which we are bound to experience over and over for eternity.
OR
This actually is the first time we have lived, so you better be satisfied with the way you have lived your life, because you may have to relive it for eternity.