Sometimes, when we're feeling depressed or anxious, it can be very hard to do anything. Even the simplest tasks can feel too much.
A strategy that I often give to clients to use is:
"Follow the plan, not the feeling"
When you are struggling to find the motivation or mental energy to do something, this strategy can help. If we follow the plan rather than waiting till we "feel like it' or 'are in the mood' - to exercise, meet someone for a drink, clean the kitchen - and do the thing that we keep putting off, we can feel better.
The theory part:
How we behave can maintain our anxiety or depression, so changing our behaviour can have a positive effect on our thoughts. This strategy shifts the focus from trying to change how we're thinking on to changing what we're doing. Which feels more achievable.