Disillusioned

I work so hard to keep a good attitude, but sometimes I find myself wallowing in the disillusionment of being a mom. What I mean to say is that it isn't what I once thought and hoped it would be. Of course everyone knows that you can't know what it's like until you're in it, but I have one child who to me is a complete puzzle. And while I don't want to go into detail complaining about the problems we face, what I need to express is how painful it is to have a child who has desperate needs and to find myself so mystified about how to help or what to do. I have taken parenting classes and read many books and prayed at length and talked to counselors and other moms and still have no idea if anything I'm doing is getting through or making any difference. I feel so helpless and even more disillusioned as the mom in this relationship. I've always been so confident in my life that I could face whatever comes my way but this has beaten me down time and time again until I feel completely at a loss and incapable of facing the challenge any more. I've never been one to run away in the face of adversity, but I want to run and never look back sometimes. And then I feel guilty about it because that's not what "good moms" do. They don't run away from their children. They love them unconditionally and help to solve whatever problems arise. But what do I do when I'm SO TIRED? I turn to the Lord again and again and ask for His help. I feel like each morning I wake up and just say "Help!" to the heavens, but somehow I feel so inadequate and still so incapable. What makes the whole situation worse is that I feel like I can't address the needs of the household because I'm so mentally zapped--like the laundry, cooking, and cleaning. So then I end up feeling like a slob. Where am I in all of this and where is God leading me? Is it just my challenge to endure it and keep trying, or is there a lesson in this that I am completely missing so I can't move on until I learn it? I promise I'm trying so hard to be who God wants me to be and learn what He wants me to learn, but I'm so tired and sometimes to just keep trying seems too overwhelming. Where are the answers and will I ever find them? Or is this child's life just destined to be hard and confusing? How do we find our way through?