Isn't this forum great - Concensus is that you can expect this, but if it lingers too long, or you have if you have harmful thoughts- you know what to do. Personally, (as a woman, artist, and runner) I can remember extreme frustration that I coined as "depressed". Then I had some friends who were clinically depressed straighten me out. If you can "pick yourself up by the bootstraps" then you are experiencing a normal response to the 'change' and surgery. Someone else mentioned it, but Steroids have an effect, and it throws your hormones off for a while after you finish your last round. My docs cleared me to do normal activities fairly quickly, but they are eternal optimists. I remember the first time I put on my running shoes my dogs (three big ones) almost bowled me over. I ran a total of 8 steps. My dogs have learned to wait with bated breath, and me too. You are fortunate that you don't have many vesibular issues, but you had brain surgery. I'm hopeful you will get back to running and you will self regulate your hormones that way. For me, the energy boost running or working out gives is not there yet, and I instead, have to sleep. Now, I am being told 5 years to reach optimum: what pessimists! For me, I think us artists (and others) tend toward perfectionism, and then when it doesn't work that way, we adapt. I think now, 4.5 months after my surgery I really only need spritual guidance, and you can get a dose here.
Off to go run/walk my couple miles!
Jules