Holy Communion is for baptized Catholics in a state of grace, who are properly spiritually prepared and disposed to receive. If you are not in a state of grace or unbelieving, the spiritual consequences to you are very serious. St. Paul on the subject:
Corinthians 11:27-29
So then, whoever eats the bread or drinks the cup of the Lord in an unworthy manner will be guilty of sinning against the Body and Blood of the Lord. Everyone ought to examine themselves before they eat of the bread and drink from the cup. For those who eat and drink without discerning the body of Christ eat and drink judgment on themselves.
“Perfect contrition. Sorrow for sin arising from perfect love. In perfect contrition the sinner detests sin more than any other evil, because it offends God, who is supremely good and deserving of all human love. Its motive is founded on God’s own goodness and not merely his goodness to the sinner or to humanity. This motive, and not the intensity of the act, less still the feelings experienced, is what essentially constitutes perfect sorrow.”
All holiness is in the will.