Being lost in guilt and shame is like being lost in a forest at night; overwhelming, dark, and scary. You have no idea what enemies lurk or that they are ready to attack during this vulnerable moment. Guilt and shame are not of God and we must learn to immediately withdraw from moments of guilt and shame before the enemy attacks during this vulnerable moment.
Conviction is of God and requires a heart ready and willing to turn from sin and to allow God to cleanse you. Conviction is the light helping you see in the dark. Repentance is finding the right path to take. Cleansing is finding your way out of that dark forest you were lost in.
When guilt and shame creep in, tell the devil what he can do with his lies! YOU are a child of God!