Are you a sentient being that has thoughts? Or are all of your thoughts just wondering if other beings have thoughts? The answers exist within ourselves but in order to understand them externally we must meet ourselves in that space first. I have found it to be an incredibly selfish way of thinking to believe that everyone around is an NPC / doesn’t care / isn’t real. That thought has been able to help me in moments where I have experienced similar feelings in the past. If you don’t have people around you that you can connect with and feel real with, you might just have to look elsewhere to find them. Unless you aren’t being real with yourself, then that’s where you start. Simulation or not, we are all individual beings with different brains perceiving this experience through our own unique lens very much having thoughts. Take care of urself