Fear of failure is strong. We actually do things to sabotage success. Maybe we fear success brings too much responsibility. Maybe you'll be expected to keep up with a standard of faith and practice you don't think you can sustain beyond your current zeal. Do you put more effort into avoiding failure than into being can-do oriented?
Maybe you think things are going too good and at any moment the rug is going to pulled out from beneath you. Do you have the self-destructive tendency to help your sabotage along? I know I do.
Samson comes to mind. What was that guy thinking? God hand picks him before He is conceived, his parents raise him right, God uses him incredibly, and he constantly sets himself up for failure. He went straight from miraculous victory to self-centered, self-destructive malfunction.
He picked fights that caused the death of loved ones. He dated a neurotic beauty queen bent figuring out a way to exploit his secret weakness. And Samson stayed with this woman.
And God used him.
It kind of gives me hope.
Be encouraged. God uses the small things of this world to confound the great, and the foolish things to confound the wise. I'm pretty sure He can work with you.