Sorry for taking so long to reply to your question. It sounds like you use to walk with Jesus, but after you did some particular sin you feel like he does not walk with you anymore, and this is why you don’t feel like you have peace with him? There are a few things I would like to make clear from the bible about sin, peace and feelings.
Don’t worry about anything, but in everything, through prayer and petition with thanksgiving, let your requests be made known to God. 7 And the peace of God, which surpasses every thought, will guard your hearts and your minds in Christ Jesus.
This is a key verse when it comes to peace with God. Notice that it comes through prayer. I suspect that because of your sin you feel distant from God and perhaps not able to pray? It is helpful to remind yourself as a Christian what God has already done for you in regards to your sin.
‘But God proves His own love for us in that while we were still sinners Christ died for us!’
Jesus died to pay the full price for our sin. Past, present and future sins are paid for in full by Jesus death on our behalf. Notice what we were like when Christ died for us… while we were still sinners… Christ died for us. In other words, when we were at our very worse… even enemies of God, Christ died for us, that is how much God loves us. So what ever sin you committed, it is not outside God’s ability to forgive you. In fact if you trust in Jesus death on your behalf you are already forgiven.
It might be a matter of asking God to help you forgive yourself. We will continue to sin, even as Christians.
‘If we say, “We have no sin,” we are deceiving ourselves, and the truth is not in us. If we confess our sins, He is faithful and righteous to forgive us our sins and to cleanse us from all unrighteousness. If we say, “We have not sinned,” we make Him a liar, and His word is not in us. My little children, I am writing you these things so that you may not sin. But if anyone does sin, we have an advocate with the Father—Jesus Christ the righteous One.’
1 John 1:8 - 2:1
In regard to trusting our feelings I would just want to caution you in how much we can trust our feelings to match with reality.
And this is the testimony: God has given us eternal life, and this life is in His Son. The one who has the Son has life. The one who doesn’t have the Son of God does not have life. I have written these things to you who believe in the name of the Son of God, so that you may know that you have eternal life.
1 John 5:11-13
John writes to Christians so that ‘you may know that you have eternal life’. He would not need to do this if they ‘felt’ like they do have eternal life. So I would caution trusting in how we feel, and try trusting in what we know God says is true in his word the bible. So if you have ‘the son [Jesus]’ then you will also have eternal life and peace with God regardless of how you feel.
So my advice is to say sorry to God for what you did, then thank God for Jesus’ death that has taken your sin away, and ask for God’s help to live life his way more and more.