Erma Bombeck, I believe it was, said if you just clean your kitchen (or perhaps it was the bathroom - I forget which,) you will feel very much as though you have accomplished quite a lot.

You sound quite overwhelmed, m'dear. You display all the symptoms, including the overbooking, forgetting commitments, etc.. But I think you have already seen some very good advice above, the best of which is to take good care of yourself.