I'm so sorry that you are suffering this way. You seem to have so many reasons to be feeling the way that you do. The feeling of fraudulence is so enmeshed in depression. All I know is that without medication I'd be unable to cope. With it I am 95% OK. I'm so sorry your poor husband experienced this trauma also. I don't know how to approach him in a reassuring way. Maybe some information you can find on this site might help him see your situation as the disease that it is. Maybe if you let him read some of the entries on this forum and let him see that you have much in common with other sufferers it might help. I don't want to advise on that because it is too delicate and I don't know him. But for you, since you have had experience of relief with medication then I'd at least consider it.
Please feel free to post here. Many people here will understand how you feel and give you some support while you decide what to do.
I hope you feel better soon.