Hebrews 8:12

I will be merciful to their unrighteousness, and their sins and their lawless deeds I will remember no more.  

God is serious when He said when we are born again; He will no longer remember our sins.  God does not hold our past up to us and say what a horrible person we were.  His plan would not work for our lives if He did.  We should not keep feeling sorrow and regret over our past mistakes. God’s plan for us counts on us believing in His mercy and love.