So you've confessed your sin to God and you were forgiven. However, a few days later, you start feeling guilty about it again. You have let satan dredge up that sordid sin again even though you have been previously forgiven. The joy of forgiveness received from God is that God doesn't remember the sin once He has pardoned you for it. However, because we are humans, very erroneous ones i.e., we, not God, falter and just can't believe that He forgives us just like that!
Guilt destroys our confidence. We feel insecure and carry around this awful feeling. Guilt damages our relationships. We feel inadequate and focused on such inadequacy that we fail to focus on our loved ones. Guilt keeps us stuck in the past. We cannot move on or try to make things better because of that burden of guilt we carry around.
But this is the exact reason why God is such a loving Father that He forgives us of EVERYTHING! Everything that bogs us down, everything that satan lied to us about. God said "I, yes, I alone --- am the one who blots out you sins for my own sake and will never think of them again." Isaiah 43:25
"Though your sins are like scarlet, they shall be as white as snow; though they are red as crimson, they shall be like wool." Isaiah 1:18
Furthermore, God forgets! Psalm 103:12 says "As far as east is from the west, so far ha he removed our transgressions from us."
The best advise I can give anyone who is guilt stricken, and we are all guilty of this, is to let that burden go. Ask God to forgive you for whatever it is that is still eating you up, know that He WILL forgive you, and once forgiven, lock it up in the forget closet and throw away the key, because God did. Release and free yourself from it and move on. You will feel so much better, I guarantee it. Keep it locked up, don't try to get it back out! That would be so silly!
Until my next rant... LOVE ONE ANOTHER!