Before you believe something, just ask yourself: "Where did I get this information from?"
Do not be stressed out about unconfessed sin before communion. Communion is not an "inventory of your sin"—it is a celebration! Preachers tell you to examine yourself for unrepentant/unforgiven sin before you eat communion so that you do not eat "unworthily." (Completely ignoring the context of what the Corinthians were doing.) News Flash: You have no unforgiven sin! Your sin (past, present, and future—all of it) was handled at the cross—once and for all (Heb. 10:14). You have been "perfected for all time" in Jesus. God is not keeping a record of your unrepentant sin as He remembers it no more. Communion is a time for celebrating Jesus' finished work and looking toward His second coming. Instead of fixating on failures, focus on what Jesus already did! If you believe and trust in Jesus, if you profess the name of Jesus, then you should be partaking of communion. Period. No church has the authority to prevent you from partaking, even if you are merely visiting them!
Jesus was crucified on the cross long before you were born. At that time, all your sin was future. The idea that you have future sin you might commit that you need to ask forgiveness for is unbiblical. When you come to Jesus, His righteousness is imputed to you and your slate is wiped completely clean. "You have been made complete" in Jesus (Col. 2:10). "His divine power has given us everything pertaining to life and godliness" (2 Pet. 1:3). We lack nothing! The perfection, righteousness, and holiness required by God is provided to you by the New Covenant. It is an eternal and unconditional covenant because God swore it by Himself and fulfilled it through Jesus (Jer. 31:31-34; Heb. 8:8-12). Stop asking Him for forgiveness and start thanking Him for His forgiveness! "There is now no condemnation for those who are in Christ Jesus" (Rom. 8:1).
Embrace the truth and live free!