I hope you will find some of the answers in this post that will help you, we have talked about many of these before but they get buried so here is a reminder.
Here are suggestions:
Any kind of Exercise. Exercise gets the body to release very pleasant chemicals and neurotransmitters. And you can also feel better about living healthier and eventually looking better.
Exercise is certainly a good wake-up call for our bodies and makes us feel better, but before you rely on that solely please have a good check-up by your doctor. Ask for a T3/T4 thyroid test as well and also get your adrenal gland checked. These are two organs that can cause lethargy, panic attacks, depression from both
You could talk to a therapist, doctor, or psychiatrist; you may need an anti-depressant.
For me it was exercise, therapy (cognitive behaviour therapy is supposed to be the most effective) and anti depressants. I'm weaning off the drugs and i'm still happy (not all the time, but enough, like an average person).
Try watching comedies when you are alone. And try organizing gatherings with friends during the weekends. You will feel better if you are preparing for something, and you will have fun hanging out with friends.
Organising events is usually the best way. I try to make myself feel better by doing something I enjoy, listening to music, shopping, playing with my dog. I plan time into my day for just me.
Other ideas: 1) get a pet. Something you can take care of. Usually when you feel bad, you can also end up quite lonely. 2) change your surroundings: move your furniture or try on a different outfit. 3) get an organiser- related to the one above, try to fill your days with something to do. 4) go somewhere- anywhere. Go for a walk with no direction. Don't get lost, but do go for a walk and take a look around you. 5) try cooking/cleaning - sounds too domestic, but often when you cook your own meal, or clean up your home you'll pleased with what you've accomplished
Get some sun. 
Think about positive aspects of your life.
If you're unhappy all of the time: 1) Talk to your most supportive friends. 2) Write down the names of ten people who care about you & of people you care about. 3) Find a way to cope with your depression like: reading, writing, or drawing. 4) Hurting yourself is NEVER the answer
CBT
Realistic Thinking: when you have a thought that makes you worry or feel unhappy, ask yourself if it is realistic. Unrealistic worries are often to blame when we feel bad. If the thought is not realistic (for example, thinking that you will never feel better, or thinking that everyone hates you), then you tell yourself "Realistically ..." and reframe that thought into something that is actually real instead of blown out of proportion (for example, "Realistically, I will feel better sometime, even if I don't feel good now" or "Realistically, some people like me and some people don't - everybody has some people who don't like them").
Examine the Evidence: whenever you feel overwhelmed and depressed, look at the facts surrounding the situation. Things are almost never as bad as they look when you are upset. List the facts - both good and bad - on paper or in your computer so that you can be more scientific about it. This ties into reallistic thinking.
Find Your Triggers: keep a mood diary to figure out what things set off these unhappy feelings. The more you know about your emotions, the more in control you can become. If you know that you always feel sad after talking to a certain person, then you can decide if it might be best not to talk to them, or you can prepare ahead of time and figure out how to avoid feeling bad from the conversation.
Mix it Up: try changing your routine, even a little bit. Sometimes doing something different will help you change your mood.
Do something JUST FOR YOU. The point is to actually acknowledge your own value. Make yourself a Queen or a King for a night. You are very special and you are important.
Now let's hear it from you...........how are you going to apply the above to make yourself feel better????
Kitt