I feel your pain and recognize your emotional exhaustion. I'm fairly certain that I'm not a terrible person, but I'm always on a razors edge of maintaining control. Almost feels like rage is actually my base emotional state and I'm in a 24/7/365 battle against myself. It feels like I resent people in my life because they can't possibly imagine or respect the energy and effort that I'm putting forth literally every moment of every day. Just to maintain a baseline close to normalcy. And that I'm JUST SO TIRED all the time from the effort not to being in a state of rage.
I've always struggled with these feelings but at this point in my life... I just feel absolutely broken. I'm 40 now, and I've never had healthy relationships (big surprise). About 2 years ago I had a fiance who was one of the most intelligent, kind, empathetic people that I've ever known. I tried so hard to stay in control, I knew how lucky I was. And when I lost my temper, even over small things, he was understanding and forgiving. He was the only partner I ever told about my ADHD and related struggles. FFS after he moved in with me, he even started a regular guy's night with his friends to give me one evening a week that was always scheduled for me to just be home by myself and be lost in my own neuroses. One day, he asked why I seemed upset when when he changed his plans and came home a little early to see me. He didn't understand why he couldn't just stay in another room of the house to let me have my "alone time". I made a mistake and decided to try to explain. I tried to explain how much mental energy I had to expend just on the drive home from work EVERY DAY simply to be prepared to interact with him when I got home. I tried to explain that it was BECAUSE I cared so much that it took so much mental effort to be with him. That it just wasn't possible to relax my mind if he was even in the house. He was hurt, he was confused. He said that if it took so much 'effort' for me to be around him, that it wasn't right. He left. We tried a bit to reconcile, I tried so many ways to explain. He just couldn't understand. I was angry at him, but I was incensed at myself. I've realized that I won't ever have a "good" relationship. Not even just a friendship. I will forever be alone, I will forever feel like an imposter in my own life, and I will forever be tired.