Is this unhealthy or nothing to worry about?

I've gone to dinner with my family and their friends and I just ate like not even half of what was on my plate and they where all so shocked that I was already finished.

They where all like "You need to eat a full meal! You're not eating enough"

And I just feel this spark of accomplishment and happiness. This also happens everyday at lunch during school and dinner but no one judges me about not eating breakfast because no one "eats" with me. I catch myself feeling that way and I even scare myself sometimes so like is this something not to worry about??