Having worked in the school system, and having also experienced some persecution - even sexual harassment by some female teachers in one setting - in more than one school, my impression is that there are groups out there sometimes who are trying to get rid of those who are not of their particular group and/or persuasion of whatever kind.
They hate you for being different, for daring to stick to your values, rather than going along with theirs. I believe this is because in the deep recesses of their hearts they don't really feel secure in their choices so can't stand any who don't go along with their ways. My impression is that some of those types of people are secretly miserable. Pray for them!
My solution was to keep covered with prayer and listen to that "still small voice" guiding and protecting me. I pray that for you and for peace and healing. If they are persecuting you, directly and/or indirectly because you are a Christian, maybe calling you a "bigot" or whatever behind your back, rejoice! Messiah said that those who are persecuted for His sake should rejoice because great will be their reward in Heaven.
Don't get angry. That is one thing they are hoping for. Angry people are easier to control. Pray for them, as we are told to do. Bless and don't "curse."
Be kind, be loving, do your job and trust in the Lord to get you through. Also, though, the Bible does say that if you are persecuted in one town you should flee to another. So prayerfully consider leaving that school when you can, with guidance as to where to go. I did that.
I pray all will work out well for you.