is it weird/bad to order food from the restaurant that you work at?

NO absolutely NOT! They probably would love it as you are investing in the company you work for and you are actually eating the for you are trying to sell therefore you can give be even more informative to your customers.

I'm a cook in a restaurant and i've also worked from of the house and I've always done that in whatever food job i've worked in and no one has ever complained or given dirty looks.

In my opinion its not weird or bad but maybe a change of taste of food may be welcoming during your time off. Usually, if you worked in a restaurant you got to get one free meal a day and having worked assuming 8 hours a day sometimes 6 days a week, you sure don't want to order those familiar food and smell of food during your off days *