So have you gone to see a doctor? Altitude sickness doesn't last that long. As far as elevation, I find exhilaration from being higher up. For a couple of decades, I lived above 9000' and couldn't wait to get home from work. Even now, one of our favorite places to camp is up on Grand Mesa, above 10,000'. I love hiking and camping above timberline (around 12,000' +/- here) When you talk about anxiety and low grade depression, perhaps something else is going on. I'd talk to a medical professional just in case.