Change behaviors that feed depression and anxiety, and change the feelings of depression and anxiety.
Depression is insidious because it pulls you out of the very things that nurture you. You get depressed and you start pulling out of social support, physical activity, and meaningful activities. The more you pull out of these things, the more it makes you depressed. The more depressed you get, the more you pull out of these things. And on and on it goes. This is the Loop.
Anxiety is very similar. You start feeling scared about something, so you start avoiding it. The more you avoid it, the more you believe that this thing is WORTH AVOIDING AND IS ACTUALLY DANGEROUS. So you feel more scared about that thing. And you keep avoiding it. And feel more scared. And on and on it goes. You guessed it. The Loop.
The reason the Loop works is because there are behaviors (like shutting down, pulling out of support, being inactive, avoiding things) that will actually make you more depressed and anxious. I could take a non-depressed person and make them sit at home, stay in bed, be inactive, and avoid doing things that they find meaningful. And in time that person would become depressed.
Part of healing from depression and anxiety is stopping the Loop. One way to do this is by using OPPOSITE ACTION. You change behaviors that feed into depression and anxiety, and you stop strengthening the feelings of depression and anxiety. When you change behaviors you start doing things that feed other emotions, like joy, confidence, peace, and self-love.