Can your supervisor deny you bathroom breaks?

I’m a daycare teacher and we have certain state ratios with the children to maintain. This basically means I’m stuck in my classroom for the whole day until my lunch break when a floater will replace me for an hour. I work 8:00am- 5:00pm/5:30pm and my break is 12:00pm-1:00pm.

From 8:00am-12:00pm and 1:00pm-5:00pm/5:30pm, I’m not allowed to go to the bathroom. I’m starting to get nervous about eating or drinking anything in fear that I might have to use the restroom and won’t be able to. If I call my supervisor and ask, she’ll usually give me a hard time and I literally will have to beg to go.

Is this legal? Can you really be denied a bathroom break?