OMG!!!
i would write a formal letter of complaint to the school administrative board & principal, and cc: the 'counsellor' and school teacher in. they need to know what they did was compeltely unacceptable and that throwing out b.s. excuses like only "skimming" it only further attests to their refusal to take responsibility for doing something wrong.
i am so, so sorry this has happened to you, sweetie. i guess the other question/thought is whether you have told your therapist? maybe she has some better ideas on how to approach this, or whether it is best to leave it alone? what are your thoughts on the matter?