I haven’t written a book like this, but I’ve often thought about writing a book called The Sensuous Christian, describing one who lives and dies by his feelings.
It doesn’t matter what you feel—if you’re forgiven by Christ, that’s an objective state of affairs. If you’ve confessed your sins, God has promised to forgive you for your sins. If you confess your sins, then your sins are forgiven. It doesn’t matter how you feel.
You may still feel guilty. Conversely, let’s say someone commits a crime, goes to the courtroom, and the judge asks, “How do you plead?” Then the person says, “Not guilty.” If you ask, ”Why?” and he says, “Because I don’t feel guilty,” we recognize that not feeling guilty is no proof of guilt or innocence. Not feeling forgiven is the same thing.
So, I would say that you need to look at the objective truths of Scripture. See what it is that Jesus teaches about salvation. If you trust in those words of His teaching, then you can be assured that you are in His kingdom. But as soon as you start resting on your feelings, you’re cooked.