Have reading books with eyeglasses for a very long time. Is so, it is normal. You are just tired and need rest. If you get headache once you wear the reading glasses, i think you may go wrong prescription eyeglasses. So, you'd better back to an eye doctor and get an eye check again. Just make sure you wearing the right prescription eyeglasses if you want to get better vision.
Well, generally speaking, it's normal to have a headache when you wear Reading glasses, especially when you have read a book for a long time. I think maybe it's because you are tired. So you can just take off your reading glasses and go outside to relax your body and your eyes. Because if your focus on one point for a long time, it will increase the eye strain and lead to a headache. It you still have a headache after you have a good rest, you may go and see a doctor. I think he can check out the other reasons.
You've got the reading glasses which may help you see the near things clearly. I think your problem must be caused by the maladjustment because you wear the reading glasses for the first time. However, there is another reason that may cause you feel dazzle when reading. That is prescription. Maybe the prescription the glasses take is a little higher for you. Thus, you'd better go to see the doctor and have the check.