Dear Dan,

Thanks for the question.

Most Catholics are not aware that every Friday is a day of penance since the change — post-Vatican II (whereas now, only the Fridays in Lent require abstinence from meat.)

The conventional understanding became one of "Only Fridays in Lent count," which is a complete misunderstanding of the change.  

In essence, in an effort to empower people by giving them an option to choose the nature of the weekly sacrifice, whereby they could become more involved in earnestly thinking about how to perform their penance, the Church let the practice fall into obscurity, and instead of being empowered Catholics, are uninformed.

So, your sin is merely venial because you didn't know.  

I would try starting a new practice or go with the old-school way and skip meat on Fridays.  Either way, whatever routine works best for you is fine.

Peace,