In my experience unless you have or have had depression you just can't empathize with those that do. I don't know how many times I have been harshly ordered to "snap out of it" by someone that cares about
me but just doesn't get it. In a lot of ways it's about
the worst problem you can have because it's so stigmatized by society. You're seen as lazy or "attention seeking" when it takes all your strength to even get out of bed somedays. This lack of empathy by family, friends and society contributes to many depression sufferers eventually committing suicide. We feel alienated and discriminated against and we just want some kind of relief from something somewhere, or at least for people to cut us some slack when it gets really bad.
If your husband doesn't understand, find a support group or a good counselor to talk to. Than at least you won't feel like it's you against the world.
On another note, you might consider getting some extensive blood work done. There could be an underlying physiological cause you aren't aware of. I strongly feel that mine was related to malnutrition as a result of Crohn's Disease because once I started taking iron and B-12 my depression symptoms lessened significantly. I've also had some luck with vitamin c megadosing, but that can give people the runs so I don't recommend it without reading up on it a lot first.