Hi, Jeanna
let's see, it's summer, sunny and bright in the States, and in Melbourne it's chilly and cloudy. That can't be helping your state of mind any. But spring will be coming. I get stretches of days that are very hard to bare. I have found that meditation help me to calm my mind and not see life thought such a dark lense.
Maybe you could try a little experiment. Make a list of all you have done to help your husband - including the courage to care for him to the detriment of your job. I'm betting its a pretty long list. Now, ask yourself, which of those things were done by a strong person, and which by a weak person. When you find that a strong person did most (if not all) of them, look in the mirror and tell yourself you are strong. I think you are!