, remember how much He loved you and how much He sees your worth. You are someone He traded the heaven for, you are the joy that He saw beyond the cross and you are His beloved child. And it is not because you are good but because He is good.
Now, try to live out those truth and turn away from any insecurities that the enemy is planting in you. Just imagine how disappointed Satan would be when you rebuke it and say "not today, I know who I am in my Father's eyes and that is enough for me to know that I am valued, loved and known." And that is where your joy should always come.