I want to repeat for emphasis what a few people have said above: you can't do anti-depressants without a doctor.
Anti-depressants require a prescription. That is for a good reason. Different people react differently to different drugs and you may not need drugs at all. If it is a mild depression a doctor may start you out on a change of diet, routine and exercise. Or be able to direct you towards some good counselling. Or you might need drugs and a doctor will need to supervise that with you.
As for addiction, Principessa is right - there is a world of difference between having a drug help you feel better and addiction. As someone once put it to me, "I'm not addicted, I'd just have a lower quality of life without them".
Go to your GP and tell him/her what you told us.
If you really don't want to go to a doctor then are still some things you can look at yourself:
- When did you start 'feeling crappy' and was there a specific event or series of events that occurred at the outset of this 'feeling crappy'? (i.e. what has changed in your life, if anything?)
- Lethargy can be an issue. Do you get much exercise in a day? If not have you time to add some in? Something you enjoy - not forcing yourself to go down the gym if you hate that. I'm a stroll in the park kind of person. You might be a swimmer or runner or tennis player, etc..
- Routine can be an issue. Are you doing the same ol', same ol' day in and day out? Can you add something new in your life to give you more variety? A new hobby, a weekly trip to the cinema if you like that, an evening class, a book club, whatever, as long as you can enjoy it.
- Look at your diet too. Cut out things like caffeine, eggs and dairy and dramatically reduce wheat products. See how you feel. Then slowly reintroduce them one by one, a week at a time. See how you feel. The foods I mention there are more specific to diagnosing a migraine cause but they are among the chief offenders of foods than people do not realise are having an adverse effect on them.
If you are depressed those above steps may do absolutely nothing for you. I'm not suggesting that all depression can be cured by stopping to smell the flowers and drinking less coffee. It can't. But if you don't want to go to a doctor yet it is worth taking a month to try it - and then, if you do go to a doctor, you can tell him/her that you've done all that.
Best of luck with feeling better.