It does sound like you are having a rough time. Depression is complicated. Do you have someone you can talk to? A friend, counselor, therapist, someone who is impartial and can listen to what you are going through. As for the specifics, the exercise plan, don’t beet yourself up, start small and work your way up. If one day you can only do part of the plan, do part of the plan and tell yourself it is ok you only did part of it. Over time you will start working your way up, you will be able to do the beginner exercise plan, and you will keep getting better. Same with emotional eating. Don’t be too hard on yourself, set small goals, and small rewards and work your way up to where you want to be.
I am assuming that you want the testosterone because you are transitioning or something like that? It is not my business so do not feel obligated to confirm. If that is it, then I hope you are working with a doctor or psychologist that works with the trans community to help you along the way. They may at some point prescribe testosterone for you. In the mean time know you are not alone. many people go through these things and there are communities that can help support you.
Lastly, most schools have councilors you can talk to. They are there to help.
Good luck, it will get better.