Sick leave is not vacation days; it is designed to let you avoid coming to work sick (and so potentially infecting others; and also recover more quickly than if working while sick), without losing income. If you don't work, there is no need for sick leave; sick leave is, again, so that you can miss a day you would otherwise have worked without missing pay. If you did not work, you would not be entitled to sick leave; you don't get sick pay for staying home days you were not scheduled to work anyway. So if you have not worked at the district this school year, it would be appropriate for them to deny you sick leave.