I am so so sorry you both had to endure this, my deepest, deepest condolences to each of you...
Reading your post gave me the strong indication you both are very compassionate. Believe it or not, when things like this happen sooner in life, it makes you so much stronger to deal with things that happen later in life when so many others don't know what to do...
This makes you appreciate what you have left, thus making what you have left more stronger than before... Your husband is your family, and he didn't die, neither did you...
Depression happens to just about everyone, no matter the circumstances, the main goal is to be sure to reach out to others close to you both..Grieve together, get counseling if you must, talk it out, cry, write it down, burn it!
Confront it, deal with it, it will get better...
Take as much time as you both need to deal with this, the pain of loss will always be with you, but you both can use it as a tool rather than a dagger.... With each other, you can become strong, sharing everything, each others pains, sorrows, in the long run you will both overcome!
If you believe in God, then reach out to him!
I have been married for 18 years, I have seen so much loss over the years, parents, grandparents, friends, it made us stronger than ever before!
Talk it out, cry it out, write it out, reach out, but do it together!
God Bless you!