DON’T go to communion if you’re in the state of mortal sin. You MUST go to confession first. A person in mortal sin who goes to communion receives Our Lord unworthily. 1 Cor. 11: 23-32:
[23] For I have received of the Lord that which also I delivered unto you, that the Lord Jesus, the same night in which he was betrayed, took bread.
[24] And giving thanks, broke, and said: Take ye, and eat: this is my body, which shall be delivered for you: this do for the commemoration of me.
[25] In like manner also the chalice, after he had supped, saying: This chalice is the new testament in my blood: this do ye, as often as you shall drink, for the commemoration of me.
[26] For as often as you shall eat this bread, and drink the chalice, you shall shew the death of the Lord, until he come.
[27] Therefore whosoever shall eat this bread, or drink the chalice of the Lord unworthily, shall be guilty of the body and of the blood of the Lord. [28] But let a man prove himself: and so let him eat of that bread, and drink of the chalice. [29] For he that eateth and drinketh unworthily, eateth and drinketh judgment to himself, not discerning the body of the Lord. [30] Therefore are there many infirm and weak among you, and many sleep.
[27]
“Or drink”: Here erroneous translators corrupted the text, by putting “and drink” (contrary to the original) instead of “or drink”.
[27]
“Guilty of the body”: not discerning the body. This demonstrates the real presence of the body and blood of Christ, even to the unworthy communicant; who otherwise could not be guilty of the body and blood of Christ, or justly condemned for not discerning the Lord’s body.
[28]
“Drink of the chalice”: This is not said by way of command, but by way of allowance, viz., where and when it is agreeable to the practice and discipline of the church.
[31] But if we would judge ourselves, we should not be judged.
[32] But whilst we are judged, we are chastised by the Lord, that we be not condemned with this world.