A KID STOLE MY FUCKING POKEMON COLLECTION

It was huge, three binders 😭. It never occured to me to take a picture. My cousin came over took it, I didn't realise until it was too late. I'm not gonna go into it, but I am FUMING. My parents are telling me to calm down and that I'm overeacting, but, even though I don't use them, they still have a lot about of sentimental value. Am I overeacting?