On Guilt and Anxiety
I received a letter from a friend describing how he had sins in his past, and now fretted that his struggles were God's judgement for former sins. He struggles to believe God loves him now and has really forgiven him. Those struggles go all the way to the point of convincing him he is not a Christian.
Here is my response:
Thank you for writing this all out for me. I hope it was good for you to get it on paper.
I think you have two things working against you. One is a bad theology, that assumes God is angry with you. He is not. God has given us his son as a gift of his love. He has given you his son as a demonstration of how much he loves you, and as a ransom to rescue you out of sin. He loves you; that is the message of the bible. He wants you with all of your sin, all of your anxiety, all of your mess. He wants you. You are precious to him.
I would encourage you to meditate on these passages. Don’t just read them, but digest them, keep meditating on them until they bring you comfort:
Romans 5:6–8 For while we were still weak, at the right time Christ died for the ungodly.  For one will scarcely die for a righteous person—though perhaps for a good person one would dare even to die  but God shows his love for us in that while we were still sinners, Christ died for us. (ESV)
Romans 8:32–39 He who did not spare his own Son but gave him up for us all, how will he not also with him graciously give us all things?  Who shall bring any charge against God's elect? It is God who justifies.  Who is to condemn? Christ Jesus is the one who died—more than that, who was raised—who is at the right hand of God, who indeed is interceding for us.  Who shall separate us from the love of Christ? Shall tribulation, or distress, or persecution, or famine, or nakedness, or danger, or sword?  As it is written,
“For your sake we are being killed all the day long;
we are regarded as sheep to be slaughtered.”
 No, in all these things we are more than conquerors through him who loved us.  For I am sure that neither death nor life, nor angels nor rulers, nor things present nor things to come, nor powers,  nor height nor depth, nor anything else in all creation, will be able to separate us from the love of God in Christ Jesus our Lord. (ESV)
Ephesians 2:4–5 But God, being rich in mercy, because of the great love with which he loved us,  even when we were dead in our trespasses, made us alive together with Christ—by grace you have been saved— (ESV)
Your sin is no match for God’s love. He has overwhelmed and forgiven it.
Secondly, you seem to have generalized anxiety. Anxiety that works properly is a gift, it jumps out at us when we are in dangerous situations and says, “be careful”. But sometimes, and this is very common with several people in our church, our anxiety is always screaming at us even when there is nothing to worry about. In those cases, our anxiety looks for something to be wrong. Very often, people with generalized anxiety latch onto a question like “am I really a Christian?” and struggle over it for years.
When that happens, try to remind yourself that God loves you with your anxiety. The sincerity of your belief will not save you, Jesus will save you. You are saved by grace, not by your sincerity or works. Your anxiety cannot stop you from being saved.
Finally, please seek professional help for your anxiety. I know one letter will not cure you, but there is hope and help available. Contact me if you need resources to seek that help.