Let’s begin by seeing the requirements for something to be a mortal sin.
first, there are three requirements for a sin to be a mortal sin. 1. the matter itself must be grave. skipping sunday mass AND reception of the Blessed Sacrament is GRAVE. it doesn’t matter what anyone says, it is grave. if you choose to skip sunday mass or not receive the Blessed Sacrament, you are basically saying your daily life and concerns are more important than God. the only case in which not receiving communion would NOT be a mortal sin is if you already committed a mortal sin, knew you did, and therefore could not receive communion. if you receive communion in a state of mortal sin, this is another mortal sin and a far worse one, the sin of sacrilege. So this would be the only reason to not receive. hopefully though you would go to confession before sunday mass and would receive because the longer you wait to confess a sin, the more numb your conscience becomes to the gravity of it and the less you care.
- You must know the sin itself is grave. if you didn’t then your freed of this because how could you be held culpable if you did not know? but usually you will know if you committed a mortal sin because God wrote the natural laws on our hearts so we know if it’s a grave sin. plus a feeling of guilt and extreme dread will most likely overcome you
- you have full consent of will meaning you knew it was wrong but did it anyway. all three of these conditions must be met in order for it to be a mortal sin. if one of them is not met, then it is not a mortal sin but instead is a venial sin. you still should go to confession though if you realized you did commit a mortal sin because this is good. which brings me to my next point:
Was this for Sunday mass? if it was for sunday mass then yes there is sin here because 1. we are required to go to mass every sunday. i know the Church says the bare minimum is once a year but the Church also says we really need to go EVERY sunday. once a year is the bare minimum. every sunday is better. 2.if you know you must go to mass every sunday but you choose to skip mass anyway, it is a grave sin and 3. the whole point of going mass is to receive the Blessed Sacrament and if you did not receive communion, then you missed your sunday obligation to receive communion thus there is sin. also you walked out on Our Lord, which is like just randomly walking out of a guests house if they invited you over to dinner, so it is rude. i will not and cannot condemn you because that is for God only and i am obviously human so i sin as well. but from what i know, i think you need to go to confession. i would highly advise this. of course like i said if you did not know then you have not done anything major but you should still go. Receive Our Lord’s mercy and forgiveness and have peace of mind again. know He loves you very much and wants you to receive Him in communion. Hope this helped and i hope im not to harsh.