Photographer on football side lines

[photo]

I am a custodian in a high school and got permission by two coachs, one being the head coach to shot photos of the game and was going to give prints to the school. Part of my job is taking care and lining the field.
The head security at this game contacted the A.D. and school principal about excorting me off the field during the game because she said it was against IHSA rules for me to be out there. This was on a Sat. and on Monday she approached me and harassed me twice about me being out there. I got permission by the head coach and other coaches to shoot the game and they said nothing, they knew I was out there.

I was not paid for the photography, all expenses were covered by me.

Is the harassment stand up about me being on the side lines about IHSA rules like she said? Was it okay by IHSA rules okay for me to photograh the game. I am employed by the school and she knew me and they all knew me.

Please help with the confusion here, thank you.

photoman