Michelle's Stern Professor by Dinah McLeod

Michelle Johnson has been down on her luck for the past year and life only seems to be getting worse. First, she's diagnosed with cancer, then she loses her job, her apartment and her boyfriend of six years one after the other. Now she has to move back in with the father that abandoned her after her parents' divorce. Life just couldn't get any worse. That's what she thought, until the only teaching position she can find is Kindergarten - her least favorite! Worse yet, the principal is her old high school crush who doesn't hesitate to punish tardiness with a special kind of detention.