Do you exercise? I don't mean go on walks, which people consider exercise for some reason, but things like running long distances/sprinting or go to the gym and lift heavy things on a regular basis. I notice you mention climbing and a trip to Asia but specifics are not mentioned. If you do not, I would try this before trying a pharmaceutical intervention which should be left as a last ditch effort. Exercise helps massively with brain function and mood be releasing endogenous compounds that aren't released in large amounts from other activities.