When I'm annoyed I usually just tell people I don't believe in anything
That's a strange habit. Do you really not believe in anything?
It's just not logical to believe in things that don't exist.
It's okay to be skeptical about things you can't see or hear. You don't have to believe in anything just because of others.
I don't care about what people think about me.
That's great that you aren't pressuring yourself based on your peers. The best way to look at things is with open eyes and not blindly trust everything you hear or read.