I'm sorry to hear you are not doing so well at the moment, that must be a frustrating thing.
If running is not possible, why not start with walking? It can be even better than running, because it's possible to have a conversation with a walking partner. The fact that you walk side by side can do great things for a conversation.
Tire that body until the mind calms down! As a marathon runner, you know what exercise can do for you.
Wish you the very best!