Not going to church is not a sin.  However, if you desire Jesus’ blood to continue to cleanse you, you might want to consider it.

“God is light and in Him is no darkness at all.  If we say that we have fellowship with Him, and walk in darkness, we lie and do not practice the truth. But if we walk in the light as He is in the light, we have fellowship with one another, and the blood of Jesus Christ His Son cleanses us from all sin.”  1 John 1:5-7

Fellowship with others is the test of whether we are walking in the light.  As we walk in the light, and that is where God is, because He is light, then we will have fellowship with others, and Jesus will continue to cleanse us from all sin.  

Now, we all want to be clean, without sin.  Yet, shame can keep us from God and others.  If you find yourself in this state, turn back toward God, confess your sins, and walk in the light with others.