My whole world and understanding of things had been turned upside down, in the best way possible

The basic summary of the cause of my illness is a familiar one. As far as I believe, the cause was burnout, plus the trigger of a nasty flu bug at the same time. From this I never properly recovered, and things quickly spiralled out of control. However, looking back at my life with hindsight, it is easy to see that there was already a foundation of issues which were affecting my health, and paving the way for a future illness.