What to do if you have been feeling upset lately?

Depends on what you're upset about. If you've got a legitimate reason to be upset, like someone you love died or you lost your job or something else tragic, you need to let yourself grieve and then move on with life. If you're just in a lousy mood, do something positive like go outside and get some exercise, or do something creative like painting or drawing or writing, or help someone else by volunteering.