You have not mentioned the terms and conditions of your appointment or your position/designation. If your appointment was for a leave vacancy or contractual, it is evident that such vacancies are usually short-term or short-lived. Some organizations have a practice of hiring casual employees for 89 days. The purpose behind such employment is to prevent them from having continuity of service by providing a break of 2-3 days.
Since this matter pertains to the school, you can contact the Education Officer of the area from which these schools receive grants.
Regards, BS Kalsi