Dramatic means having to do with a play, as in “a dramatic production.” It also means striking or exaggerated.
Half an hour of exercise a day can have a dramatic effect on your physical well being. If you burst into tears when you get a B on a paper and wail, “Now I’m never going to get into college,” you can be accused of being dramatic, which means you’re acting out your reaction, or overly dramatic, which means your reaction is over the top.