"Gang stalking" doesn't mean you're actually being stalked.
It's a manifestation of psychosis or schizophrenia. When you start believing this particular delusion, you become the center of the world. It includes believing that people's ordinary behaviors are "street theater" and that people are constantly trying to tip you off about a massive conspiracy just outside your reach, taunting you with the knowledge. People believe they are being watched constantly, they believe their friends and family are in on the gang stalking.
Most of the time, when they start this, they have friends and family who believe them, helping them try to seek FOIA requests for the government agents they know are watching, or trying to get a restraining order against whoever they've decided is the boogeyman at the center of it all.
After a few years, everyone has long since realized this person is making it up, but they join internet forums devoted to people who are victims of "gang stalking," everyone talking about how in their little corner of the universe, they are the only person that matters and everyone who speaks is speaking in coded messages to them.
I'm surprised we don't have more gangstalking types in the lolcow forums.