Depression Support Group
Depression is a real and debilitating condition that is often misunderstood by family and friends. Its meaning can range from a prolonged period of sadness to an actual mental illness with specific symptoms. Find and share experiences with others who are going through the same struggles.
You can do this unhappy just as you can do it happy.
So take the pressure off yourself. You don't have to be the life & soul. You just have to do the work, and make sure they learn about reality.
My Pdoc uses a popular Mantra: Fake it till you Make it. and it works just as it says, you don't feel like fixing supper, or doing laundry or checking homework or getting kids ready for school so you Fake acting like you're okay doing these things until eventually your not Faking anymore, you've Made it to a point where you're okay.
I had 2 sons while having BiPolar Disorder with Severe Suicidal Ideations, and there were many times that leaving my bed literally felt like it would kill me to have to use that much energy, I just wanted everyone to leave me alone.....but how do you tell that to an 8 yr old when they want dinner. One thing I've always done since I was Diagnosed BiPolar, 28yrs ago is talk to my boys about this Disease, what it tends to do, what the symptoms are, etc. I explained that sometimes it was very hard to get out of bed, but I would do my very best. When I would feel the Depression coming I would by groceries that were easy to fix. Meals that could be popped in the oven and done in 30 min. I kept paper plates and paper cups in the house, because I didn't have the energy to do tons of dishes every day and my husband worked offshore 2 weeks a month. I'd put school outfits together enough for a couple weeks, that way I didn't have to try and wade through the fog that was my brain and figure out what clothes went with what.
As much preparation you can do in advance before the Depression takes over, the easier it is. I also never turned my kids away, just because I didn't want to get out of bed didn't mean they couldn't come lay/sit with me and do homework or watch a movie quietly. I've learned that the more honest you are with your children, the easier it is for them to accept things. Kids don't like surprises or routine changes, it makes them nervous, scared, feeling unsafe. So be as age appropriately honest with your kids as you can.
Hang in there, and take care.
Kat
You've gotten lots of good advice here, mostly to take care of yourself first (and I hope that includes seeking professional and religious counsel), that you need to share to the degree you can with your children about being depressed (at there level with only the minimal information, so as not to bring them into your issue), and as for the manual, since you mention God, I'll assume you may read the Bible, it THE one (the caps of course indicating my belief, thus you have to decide for yourself). Here are two excellent articles (https://www.gotquestions.org/depression-Christian.html & https://www.thoughtco.com/what-does-the-bible-say-about-depression-701952) that discuss your question in detail, so I hope they offer relief and comfort. Know this, anyone can depressed, and it's OK, you can overcome. Just seek out the solutions to your confusion and you won't be scared: Jesus said, "Take heart, I have overcome the world." John 16:33 (And we can too!)