How can I avoid being humiliated when the teacher hands out invitations for the Honour Roll students party and I'm not invited and I'm in a gifted class?

If you are not meeting the expectations you have set for yourself, you probably should study more and see if that helps.

If you are not meeting someone else's expectations and you deem those expectations unreasonable or you do not share them, tell them to lower their expectations.

No one can make you feel inferior without your consent.