Dreams are just a melting pot of thoughts, memories, and neurons literally on an acid trip from the chemicals in our brain that induce dreaming while sleeping. But it's not uncommon to dream about things that you're anxious about, or recent events mixing and mashing information. That tends to lead to some pretty gnarly shit.
"I'm going crazy. This guy is a real person, he has been through all this shit and it's all over my life, but this guy's not even my friend. This person has never met him before."