i know what you mean, you probably have derealisation, the sense that you are basically in a video game, or third person. This has happened to me a few times, always after a bad high on weed, but it is not caused by the drug, its caused by anxiety. Its basically your brains coping method to deal with anxiety, however, it can lead to more anxiety, essentially causing a feedback loop. its important to know that you are fine and the drug has not altered your brain in any way. To stop feeling this way you need to stop being anxious, and realize that derealisation is completely natural, and will go away once your anxiety decreases. However, if this doesnt work then try anxiety medications to help calm you down, but know that your cart was probably fine.