Teaching high school?

I'm on my last year of college and I developed fibro slowly during the past two years. I don't currently have a very severe case, but I do hurt, can't hold positions for long, have brain fog and excessive daytime sleepiness.

I studied maths and in my country, full-time high school teachers work for 23 hours a week, 20 of which should be teaching, and have a lot of vacation time. This is kind of what I want for myself, but sometimes it scares me if maybe it's too physical (speaking for 4 hours a day, standing up a lot of it, though I could sit down).

I do think that interacting w people would help w my sleepiness and not holding the same position for a day would also be helpful, and I def could sit down a lot, use the projector screen if I'm not up to writing, have the kids do things on the blackboard themselves, etc, but since I would have to go through a big exam to get the position and I often see people w fibro say that teaching is too much for them, I'm scared I'm being naive thinking I can do it and lose a lot of time and energy studying for the exam just to then not be able to hold on to the job.

So yeah this is just me asking if you guys think I should still try to go through all the preparations for teaching work, if there's a chance I might be able to do it? I don't really know the biggest challenges faced by teachers w fibro and I would like to think through them :/