In order to be diagnosed with psychosis you need to experience one or more of these things: hallucinations (visual, auditory, etc), delusions, disoriented thoughts / speech. There are other symptoms, but you need to experience these for more than 3 months for it to be diagnosed as psychosis.
You can not treat yourself for psychosis, but you can join support groups both in real life and online. You don't need medication if you don't want it, but I do suggest therapy.
please see your other thread...