This sounds reminiscent of my own experiences (three plus years dealing with an as yet undiagnosed condition(s)). Regarding your first point, the most useful thing for me was finding a doctor I work well with - being able to suggest a potential cause/treatment without it coming across as "I'm the patient; I/The Internet know best" has been extremely useful. Most of the time I've overlooked something (I'll never have the same knowledge/experience base as my GP), but the few cases where it was relevant and hadn't occurred to my GP have lead to better treatments.