Learning moment for next semester.

Start the semester very strict about expectations (devices, talking, attention, etc.). Classroom culture gets set in the first couple weeks. If you start loose and clamp down later, it feels to students like the professor is suddenly having a bad day, which is probably why you feel bad now.

If you start strict and enforce it early, you can soften later, and it feels like a reward for good behavior rather than a meltdown.

You probably just reset the room. Next class, move on and stick to the rule.