When doubt settles in, it can tear at our soul like a raging bear. The gnawing in our head and our heart seems as though it will never cease. All these things are based on circumstance and emotion. Circumstances are often uncontrollable from our viewpoint. Of course, God is in control of all things.
Emotions are fickle and deceptive and utterly untrustworthy.
Things often look darkest when we are tired or guilt-ridden or emotionally spent. These are times when the enemy will do his level best to tell us that we are no good and God is done with us. That we've finally been put up on the shelf this time. This is hardly time to do this kind of evaluation with our emotions in such turmoil. On the other hand God is totally trustworthy.