12 Ways to Feel Better

Spend time with a supportive, understanding person, or a small group.
Break large tasks into small ones and do what you can. Savor each small accomplishment.
Set simple priorities and dont ask too much of yourself.
Get outside and walk for six minutes (or longer if you feel like it!).
Recognize negative thoughts (I can't do anything right. No one at work likes me. What's the point of this, anyway?) as thoughts, rather than as facts.
Forgive yourself. Everyone makes mistakes; some of us make a lot of them. But how else will we learn new things?
Enjoy the day, even if (or especially if) it's not sunny and warm. Rain can be soothing rather than gloomy. Cold weather can be invigorating instead of icy.
Laugh as much as you can. If you ever find yourself thinking, I don't know whether to laugh or cry, choose laughter. It might not be the best medicine, but it's pretty good stuff.
If you find yourself saying things like Oh, I'm so stupid, or Wow, that was dumb of me try to reframe what you want to say, for example, I'll do better next time.
Do something nice for someone. Hold a door, pick up a dropped hat, let someone turn in front of you on the street, send a card to a friend.
Talk to someone who is understanding about how you are feeling. If you want advice, ask for it. If not, tell them you just need a friendly ear.
Exercise: walk, jog, ride a bicycle, play basketball or whatever. Start slowly with something easy and build up.