Am i being watched??? Help!!?

I mean I go to high school and there is a young security guard there who stares at me for no reason and I know he spots me in a table with all my friends. He is always going by through were I am sitting down and once there was no extra chair for 6 people in the table and I was going to sit with people I don't even know and HE brought me a chair from another table (when I grabbed a chair myself he told me to put it back and he brought me the chair). I don't misbehave or anything and I am not a trouble maker so that the security guards and principal would have to keep me in constant watch. So why does that security guard do that?