Well, when I'm depressed at low levels, then I just try thinking about something else that is fun, talk to my little bro who is the closest person to me, and it becomes okay after a while.
When I'm angry and/or frustrated at low levels, I get over it after a while by repeating the steps for depression, but this time I also think how to solve the matter which made me feel this way.
However, when I'm angry/frustrated/depressed at extremely high levels, which most of the people here have probably never imagined of, let alone experienced, then I can do a whole lot.
I have a lot of problems in my life just because of the high levels of these negative emotions and the low levels of positive emotions. They badly affect me to the point to make me mentally sick.
But I can still take it. For these strong ones, I bear with myself and my mind, and plan out a way to solve them or escape from them all and start over, and this plan must work in order for me to become like a normal person.
All I want to say is that, it was only once in my entire life that somehow such emotions got free for a while, and I almost killed someone. Ever since then, I have learned to either control my emotions freely at will, or if not possible then I just bear with myself. It gets better if you plan out.