As someone who has experienced psychosis, having both ME and a psychiatric disorder, I can tell you that you don't sound like you're having a psychotic episode. Unless you're hearing voices or experiencing severe paranoia (eg. you think other people are planting thoughts in your head, etc), you're not psychotic, just pissed off.
As for running, I hope you are just venting and not serious. If you think living with this is hard now, how do you think you will do after that run? You are taking the chance of having to be immobilized, bed-bound, spoon-fed for the rest of your life. Have you seen the TED talk from Jennifer Brea (see below)? If not, I would strongly recommend that you do. She shares her journey with ME. She was also told that it was in her head, a psychosomatic disorder. She, too, decided to put it to the test, by walking home from her doctor's appointment. She was in her twenties. She did manage to make it home, but that one walk knocked her over the edge to where she was bed-bound, and she was never able to get back to her pre-walk condition. So, if you are young, and are even ABLE to run, you're more fortunate than many, and you have a chance of improving.
Also, what else have you tried as far as coping strategies? No, they won't cure you, but they will have a positive effect overall, and increase your mental and emotional stamina, improve anxiety and depression, and thus improve your quality of life. You CAN take some action, you DO have some choice and control. Do web searches for coping will chronic illness. Read books (such as "How to Be Sick" by Toni Bernhard). Watch youtube videos.There are free mindfulness meditation courses online that would otherwise cost hundreds of dollars to learn in person. Fighting and hating your body is only goint to make it worse. It's not your body's fault - it's affecting your body just as much is it is affecting you, so start having some compassion for your body and start treating it with kindness.
