pressure in raising an "only"

I just get so worn out. I want so badly not to "mess up" raising Lynn that it's exhausting dealing with "the right way" to discipline when behavior issues come up. I'm taking Shepherding a Child's Heart study by Ted Tripp and believe in his core belief that it's not about raising a child that simply behaves well, but that it's the heart that I desire to change and mold and become like Christ. I mean, that's my strive - to reach towards the holiness of Christ. No, I will never ever attain perfection - definitely not! But, by walking in His Word, He can mold me and shape me to be more like Him, like He desires, to be used by Him. I don't want Lynn to grow up behaving like the perfect child, only to turn when she gets older because I'm not there to "make her." I want to raise her that she can one day make decisions on her own that will honor God (& consequently us).
I know there is no perfect, 1-2-3, easy method of child-raising. I know that no one ever gets it right all the time. I know all that in my head, but my heart sooo yearns for her to want to know Christ and let Him be her only guide that my humanness just gets in the way. I feel crushed and disappointed (& angry) in hearing of her behavioral "issue" at school today, but I can't take it personally. That mommy guilt, man, it's a doosey. And I know that for me, that has become more magnified because of losing Nathan. It's like, "She's my only one - we can't screw her up" pressure -- totally self imposed and ridiculous, but hey, I'm being honest, it's there.
Pray for me and my hubby - just for God's wisdom in raising our strong-willed little individual. One with her own personality and character and who is so moldable and still so young. I love her dearly.