Sometimes my legs are too weak to exercise. So I ask myself what can I do today? My arms feel okay so why don't I sit in a chair and do strength training on my arms with some 3 lb weights? I feel like I've accomplished something! So I don't get completely off track.
On days when I am too weak to do much at all I ask myself, Have I at least been kind and loving today? It helps me to keep feeling good about myself.