Welcome. A lot of people here know how you feel and you are not alone.
I would encourage you to talk with your doctor. There are physical causes for depression and your doctor can help rule things out. There are chemical imbalances, hormonal imbalances and even simple deficiencies that can make you feel really bad. So please talk with a doctor. There are self-assessment checklists online that you can print off and show your doctor; it's a good place to start.
I disagree with the philosophy, "You are put on the earth to make yourself happy", but I do agree that you need to take care of yourself and address your needs, especially if you have a family. Sort of the "put the oxygen mask on yourself first before you help your seat-partner" on-a-plane analogy.
I also understand about your husband. They can't "fix" us (even though they'd like to). Just let him know that you're feeling overwhelmed right now and give him some practical things that can help.
And, please, talk to a doctor. It can get better.