I think this is something most of us stuggle with at one point or another. What's real? Knowing what we now know about quantum physics and the way the brain processes information its hard to say with conviction that what we precive as the exterior world is even real.
Imo its just one of those questions you learn to live with when you make these plant compounds a part of your life.
I think its helpful to be open to both possibilitys and to use them as lenses to examine the content of your experience after the trip.
Good luck with your travels!
Visit the Hyperspace Lexicon and contribute to the discussion. Help define the previously indiscribable! Disclaimer: Everything I say about my actions is a lie. Just because I talk about this stuff online does not mean I really do it. I don't. Drugs are bad and I love Jesus too much to do drugs.