^Excellent advice.
I used to have very, very bad mood swings. At some point I started to progressively modify my life style to try and eliminate chronic depression, which was an even bigger problem.
The first thing I did was stop being a night owl and force myself to get up in the morning, in order to get some sun. Which lead me to get into hiking a bit, since I didn't know what else to do outside.
When I moved out of my parents, I had more control over what I could eat so I started to eat less crap and more food fit for human consumption. The result was that I had more energy to get active, probably combined with my new diurnal life beat. My health also got better overtime because I had a lot of problems with my parents and their house when I lived with them.
At this point I realized how insanely connected is diet and life style with depression, mood swing and anxiety. I became more and more emotionally stable as I changed my diet and increased the amount of daily exercice.
If you are really motivated, add to it:
Less or no coffee, no drugs and alcohol, no medication, less metal music, more reggae, and some yoga and meditation.
Result for me: Depression gone, mood swing gone, brain fog gone except when I cheat on my diet, huge decrease of anxiety. I still have my issues, but I'm the more emotionally stable person I know. It's almost scary.
As Hoppy said, give yourself some months of real commitment before giving up.