Allow yourself the permission to not work right now.

It sounds to me like you are feeling low self-worth for leaving this emloyment? I don't know the circumstances but look at it as you have done yourself a favour, that you were owed this on account of your mental health. Feel no shame, feel no embarrassment.

Depression is setting in and will do so. This comes with feeling to a degree that lack of worth. But you are in fact worth it.

One thing you can do is draw up a list of expectations for yourself. What can become goals? What is reasonable and what is not?

You may have heard I and others discussing CBT (Cognative Behaviour Therapy). Maybe grab a workbook and have a go.