If someone thinks they’re being followed by higher ups every second of everyday, does that mean they’re not fully mentally stable?

This is a very touchy subject for me as my last partner was like this. I truly forgot about this and I’m trying to work through for healing. Was scrolling tiktok and ended up on an account about this guy who was staying at an Airbnb and how these Masons were stalking him and some guy down below was sending signals and how this is sex trafficking. So I scrolled his page and in his bio he mentions how hes being followed. Watched some of his vids and each one everyday is about him being followed every second like 2 teens walking to their car, they’re the government or Masons and everything of his is tapped. This woman getting into her car holding her phone, she’s apart of the higher ups. So I clicked not interested to make sure I don’t see that account or similar content again.

It reminded me a lot about my ex and made me realize the trauma I’ve buried from it. So he was constantly talking about how he’s being followed, everything is tapped, every car on the highway is an undercover cop, when he was arrested he told me his eyes were taken out and replaced, the birds were spying, etc etc. it was truly traumatic cause even a few times he told me I’m an undercover whose mission is to get to know him more and trick him. Which obviously is not true. I was scared and always on edge and feared for my safety. A few times he mentioned the cats were taken and replaced with robots to spy on him and how he should kill them. He also said his Grandma was a witch and ate them. This is when she told me she knew he wasn’t in the right mindset. So I’m wondering, is this usually a sign someone isn’t mentally stable? I know followers and sex trafficking exists, but I’m talking a normal person from the moment they wake up to the moment they go to sleep every person and car or animals are some type of undercover.

Also any tips on how I can let go of this trauma? It makes me sick to my stomach to even think about the things he’s said. I know I can just forget about it or not think about it, but that’s not solving the problem. That was the first time in 2 years I heard someone talk that way and I started reliving the bad moments of my ex going on a rant about him being followed. Suddenly the feeling of not being safe came back to me, almost threw up, and extreme anxiety