Yes, what they did to you is not fair.

I do question your T's idea about attending that school reunion. Does it really matter whether they were (or not) the same people. What matters is the impact of their abuse on you - which I think was 'missed'. Besides, abusers/bullies. rarely, if ever, admit to being abusers/bullies etc. They will downplay whatever happened. I am sorry it backfired - that sounds even more painful to have your truth and pain be dismissed and invalidated.

I just think that you also deserve to receive the care and support that you are offering Anna.

I hear that you don't want to go down the therapy route, that's fine. Maybe you can try to extend the same kindness and support that you offer Anna to yourself.