Hi cris, I agree with the above , it sounds like your husband is going through a more severe depression than he has been diagnosed with. However if he is not able to share his fears, thoughts etc with you , his only outlet at the moment, he may well feel unable to cope.
It might help you both to structure times for discussion , perhaps an hour in the morning and then an hour in the afternoon where he can unburden himself, talk through his worries and concerns but then the exact time the hour is up , it is over and he stops the diatribe that is blighting you both until the next time. Meanwhile encourage him to do something constructive with his life . You may be able to cope if you know it is only an hours duration. Don't give up, and NO you are not a bad person, a very caring one, by the sound of it all.