A CLEAN SLATE
A little boy was told by his mother not to play near a certain pond. One day the temptation was too much, and, venturing too close, he fell into the water. He was very conscious of his wrongdoing, and most uncomfortable. So he wrote on his school slate: "Dear Mother, I am sorry I have been bad. If you forgive me, please rub it out." Back came the slate, perfectly clean!
How like the love of God who said, "I have blotted out, as a thick cloud, thy transgressions, and, as a cloud, thy sins" (Isaiah 44:22)
(SOURCE: King's Business)
You need to realize all Christ has done for you. Stop being ashamed of Him. He suffered for you, in your place.