When introverts are going through shit, they shut down. They want no help. No advice. No "fixing". All they want is quiet. They know how to pull themselves out. They've done it a thousand times. Just leave them alone for a while.
Forgive your old self, you did what you knew. Let it go. You've changed. What happened, happened. The essence of life is to keep on moving. You're not what you were a year ago, a month ago, a day ago, not even a moment ago. When you accept this truth, you evolve.
Satan is going to constantly bring up your past failures, your wrong doing, your poor decisions, and your sin. He hates God’s mercy and forgiveness toward you. He doesn’t understand it. Fight back by reminding yourself of the Grace and love God has given you.