I used to have this same problem when I was much younger. Then the chronic pain appeared and I had to learn how to take breaks.
Exercise is a really good way to take breaks because it's also beneficial. Walking is a good way to get your body moving but it also can help you think. I get some of my best story ideas while walking, especially in nature. I also recommend upper body stretches and strength exercises, because that will help prevent wrist injuries that can happen from drawing too much.
I also recommend doing research! By that I mean read comics. Take a break by reading all sorts of different comics and study them to trick your brain into thinking you're not actually wasting time in anyway. All kinds of story telling media, like books and movies, can also work as an inspiration and a source of knowledge. I personally enjoy watching movies with a critical eye and constantly paying attention to the lighting and cinematography, and then draw inspiration from them. If you learn something new, that means your brain can't tell you you've wasted time.
Generally though, I think the most difficult part is just learning to relax. It's not easy, I know it isn't but in the long term it's a necessary skill. I've also noticed that after breaks, even short ones, I usually draw better and my head tends to buzz with plenty of new ideas. I personally limit my drawing time and if I have even the slightest feeling of discomfort in my wrist I stop and rest. I love my comic but taking care of my body takes priority, and that's the mind set that helps me enjoy my rest too.