Hello. I have been doing an examination of conscience and stumbled accross a doubt. I realized I had commited a grave sin and received communion after it without confession. My doubt is about the fact that when I received communion I didn’t have in mind the mortal sin (because I choose to think so, or because I didn’t really know, I’m not sure yet). My doubt is if I have to ask forgiveness and confess this as a sacrilegous communion. Thanks in advance
You’ll want to speak to confessor about this, but you have to have full knowledge at the time of sin for it to be a criteria for mortal sin.
It is better to confess it and in the future to do a better examination of conscience prior to Confession, including prayer to the Holy Spirit to reveal your sins to you and move you to contrition.
But there is sacrilege (or in general mortal sin) only when you know what you are doing is wrong and you choose to do it. For instance: “yes, I committed X which I know is a mortal sin, and I have not confessed so I know I am not properly disposed to receive Holy Communion, I know that if I go I am committing a grave sin of sacrilege, and I do not care.” And I receive Communion. If you thought your conscience was clear, there was not even sin on your side in receiving Communion. The venial sin may be a sin of imprudence for a poor examination of conscience. And in confession, all sins are absolved, even those you forgot to confess…assuming that as you remember, you are repentant and mention it in the next confession, along with the rest of the story.
So be at peace. Anxiety and fear do not come from the spirit of Christ, only peace does.
Simply confess it as you noted – tell him what happened (and if it is doubtful say so.)