Hello Roserose329: You've sustained a great loss without having the opportunity to grieve. From the Skeezyks' perspective, it is important for you to find some way to work through your grief as well as your isolation. You don't mention, in your post, if you see a therapist. If not, this may be one important step you could take. An alternative, if such a thing is available where you live, would be to find a women's organization where you might have the opportunity to meet other moms who are or have struggled with similar losses.
I know you wrote you don't want to go on antidepressants & I can certainly understand that. I've been on them as well. And they never seemed to do me much good either... mostly just made me groggy. However, the cold hard reality may be that in order to be the kind of mom you want to be for your 2 kids, you're going to have to do something. So if some type of therapy, support group, or other similar service just isn't an option for you, AD's may be the only other alternative.
The only other thing that occurs to me is that if you can arrange for child care a few hours a week, perhaps you could at least get out & do some things on your own. Just getting out of the house & having the opportunity to do some things you enjoy, perhaps with a friend, might help to relieve some of the pressure. I wish you well...