Feeling week, not being able to sleep, headaches, difficulty concentrating, various body aches, feeling low and sad etc are all as you said symptoms of depression. Since it’s been 4 years and the depression seems to have continued, you will need some medications to make you feel better.
Next Steps
Please fix up an appointment with a Psychiatrist online and discuss your problem is detail starting from its origin. Starting medications can help you get rid of this depression, as the best part is it’s treatable. Waiting will keep on increasing the intensity of depression and make you feel more miserable.