I know that I'm more self-conscious when I'm high, and this makes me give off a more suspicious vibe that I believe others can sense. Do you feel comfortable in social situations when you're high? From your example it sounds like you get a bit paranoid.

People are quite keen at detecting the mindset of others, even if they don't know they're doing it. I suspect people pick up on your paranoia and reciprocate it. I'm sure it happens all the time.