Are Lenten fumbles mortal sins?

[Onesimus]

As a shift worker, I get days confused fairly easily. This morning, I mistakenly consumed a breakfast containing meat.

Now I know I've committed no mortal sin, because it was in no way intentional, and I fully intend to go to reconciliation for my oversight. Furthermore, because I have been trying to answer the following question all day, I've discovered my practice of abstaining on Friday has not been what it should be, and I will be amending my observance.

My question is this: I cannot get to confession before Mass on Sunday, due to my work schedule. May I receive Communion at Mass before I can get to confession?

[Michelle Arnold]

If you honestly forgot that it was a Lenten Friday until after you consumed the meat, you did not sin. Assuming that you are otherwise in a state of grace, you are free to receive Communion. When you do go to confession, you need not mention this incident. As for abstinence from meat or other penances on non-Lenten Fridays, please see the article linked below.

Recommended reading:

Is Friday Penance Required? by Jimmy Akin