It means you spoke absolutely to no one, didn't see a single person or animal including from a distance, didn't hear a single person or animal including from a distance, and most importantly havent touched any form of electronics which includes the internet or a phone. For 6 straight months. Not even a small moment within those 6 months.
Choosing not to interact with others personally is an entirely different monster of loneliness than being thrown into a soulless world void of any creatures whatsoever.
Depression certainly sucks and its great you got out of it, but people confuse pseudo isolation to true absolute isolation based on the premise of this topic.
Even the most trivial interactions you dont even think of (for example seeing or hearing another creature or sounds caused by other creatures just from a distance) defeats the premise of this topics isolation. Even if its for a moment.
No electronics, but food was left at my door every so often, so that's something. I have to question your certainty of the significance of those moments, though.