Regret over sinful things I did in my past
I can understand the pain of the past you feel, but I want to assure you that Christ came for just such a person as you!
You can find total forgiveness and never live in the guilt of your past sins again, because Jesus offers to make you entirely new! That means that you past behaviour does not cause God to condemn you or to look down on you. You are now His beloved child and in His eyes, you are just as pure as the day you were born so long as you stay in relationship with Him.
I believe that the enemy has lied to you, and you received the lie because you knew about your past; and felt guilt about it. Today, you can let go of that guilt. God has made you free because of your decision to follow Christ. No one can condemn you now!
"But God, who is rich in mercy, for his great love wherewith he loved us, Even when we were dead in sins, hath quickened us together with Christ, by grace ye are saved;" Eph 2:4-5.
Please understand that you need to have a good church, that teaches about the Bible, to help you to grow in your new faith. You should also read God's Word, the Bible, and pray to God for guidance.
Linda and Charles