Hi there
As a high school teacher too, and living with CML for almost 8 years, I thought I'd also try to answer your questions:
1. Yes - you will almost certainly be able to do your duty normally. I spent only three days in hospital when I was first diagnosed and then went back to work almost immediately. I found that my work REALLY helped me to cope with my illness - as a teacher, I felt that I had to put on a brave face for my students and carry on as normal, because many of them also have family and friends with different types of cancer. From the start I decided that I would not let them see that I was worried or concerned that I wouldn't make it, and on many days I even forgot about the CML during my lessons as there was so much else to think about!
One negative was that I did find that I was more tired than usual, and I took longer to mark students' work because I was always tired at night. But I decided to take care of myself and stopped marking the minute I felt that I was too tired - it doesn't advantage the students anyway if their teacher marks their work while tired. I know that many people wouldn't do this, but I was open and honest with everyone the moment I was diagnosed. I told the Head, the students, and all the other teachers that I was sick, and the advantage of this was that I found that people were incredibly understanding when I missed a deadline or took slightly longer to mark a test. I also felt incredibly supported by my students and their parents - for example, one of them organised a surprise for me on World CML Day on 22 September, when the whole school arrived wearing orange ribbons. On a different occasion a parent organised a helicopter to come to the school for cancer awareness. All this made the journey much easier. But of course, other people prefer to tell only a small group of people (or maybe even your closest family) as they prefer to keep it private.
2. I don't think it's possible to predict when the side effects calm down as we are all so different. In my case, I had almost no side effects except fatigue and joint pain (both of which never went away). But seven years down the line in my treatment I suddenly developed such serious side effects that I had to stop my medication. I hope yours aren't too bad and that they improve or disappear completely soon.
3. I found it hard to keep myself fit. The fatigue and joint pain really prevented me from doing any serious physical activity and I have lost a lot of physical fitness. I have tried to do what I can by walking my dogs, but right now that's about all I can manage (even after being off the medication for almost six months). I'm sure others can give you better advice than me on this question!
But, to echo the advice from Alex (who has given me a great deal of excellent advice through the years) - take the tablets and try not to worry! They really are exceptional medications and I hope that you will have a speedy recovery.
Best wishes
Martin