My depressions are severe when they occur and I barely function as well. I can't even begin to tell you how much of my life has been spent in bed or a recliner watching tv. I've started making a list of 3 very small tasks...feeding my pets, brushing my teeth and meditating for 10 minutes was a recent list. If I feel more motivated I can add 3 more. If not, I've accomplished something.
It's very difficult, I know. I empathize with you.