The Life of Another

I am crucified with Christ: nevertheless I live; yet not I, but Christ lives in me: and the life which I now live in the flesh I live by the faith of the Son of God, who loved me, and gave himself for me.

If this is true then why is it that we say, ‘my faith is wavering?’ When and where is Christ ever wavering, but then maybe we see the Christ being separate from us?
I thought we were designed to bear only that which He can produce, rather than our focus being on us trying to produce faith or whatever else we think is necessary.
Is it because we really don’t have a revelation yet that we are alive only because of the life of another we’re now living out of?
If we think it is up to us to bring about in our lives a fruitfulness, then why does he say that He is the, I AM?

Rich