Kracus, the holiday laws only state that you don't have to work on certain holidays -- and if you do, you get paid more for it.
They don't say anything about only having to work 4 days in a week because of a holiday. If your employer scheduled you an extra day to make up for the lost holiday work, it's just because you work for a shitty, slave-driving company, but it's not illegal.
As long as you don't have more than 40 hours logged for the week -- or if you do, as long as you got paid overtime for it -- there is nothing wrong with it.