rest?

Lately I've been feeling a little pooped. OK, I've been feeling a lot pooped. Anyway, I'm wondering, "What does it mean to 'rest in God?'" What does it mean to be "anxious for nothing"? I think for so long I've been so amped up in crisis mode that I've missed what it means to just lay back in the Father's arms. It seems so easy. I know when my youngest son, Noah, sits on my lap, he just sits there. He doesn't struggle or try to sit on my lap, he just --- sits there. How do I do that with my heavenly Father? How do I just ---- rest?