About 1/3 to 1/2 of the year, according to some estimates! Terry Jones's Medieval Lives (this one, I think) talks about it. The point being, yes! Feast days/Holy Days were frequent (way more frequent than just Easter, New Years, etc.), and basically everyone went and feasted and socialized.

Literally all the damn time. Every Sunday, multiple feast days every month, a week during Christmas, a week preceding Easter, the week before Lent, and every 25 years a massive Jubilee that could involve multi-month pilgrimages, especially when the Jubilee coincided with the change of the century. The also drank all day, every day, dawn to dusk.