1/ Get a health check-up. First you need to know if there are medical problems that could cause your depression.
2/ Sleep: Go to sleep at regular times and get up at regular times. Don't sweat it if you think you're not getting enough sleep. But... if you can't fall asleep within 20 minutes get out of your bed and do something boring, but NO screen time (no tv, no pc). If you stay in bed and ruminate all night long, chances are that your bedroom will become a negative valued stimulus (bedroom = rumination = not feeling good).
3/ Eating: Eat at regular times. Get something in your system. If eating is difficult, then start with two meals a day, with one being something warm. Drink enough water! Try to build up from there.
4/ Get outside for at least 15 - 30 minutes. Doesn't matter what you do. Take a walk, get on a bike. Make it a habit. Do this at regular times.
5/ Divide your activities into 2 categories: leisure (L) vs need-to-do (D). It doesn't need to be something big. Pick one of each category and do them that day. No more no less. The name of the game is SMART-goals, standing for specific, measureable, agreeable, realistic, time-bound goals. Like vacuuming the living room (D), or a short walk in the park (L), getting groceries (D). Build up from there. This is behavioral activiation.
6/ Don't make the mistake of thinking you should feel a certain way before you can do something. Like I don't feel like... this is a trick of the mind and a lot of people fall into this. But don't be too hard for yourself. Just when you notice this, treat yourself like your best friend does: comfort yourself and gently pick yourself back up.
7/ Observe your feelings and your thoughts, but see them for what they are, just products of your mind. They are not real, but don't expect that you can change them, or to try to think differently. That doesn't work in the long run. This is where practicing mindfulness can be very useful.
The only choice you have is acting upon your thoughts and feelings or acting upon what you see as valuable.
8/ Reach out! It's a good thing that you're posting on this boards. Keep contact with your peers.
9/ Get into therapy, preferably Behavioral Therapy. Look in to Acceptance and Commitment Therapy (ACT)
In essence: DO something everyday, do something you don't feel like doing.