sister wears my boyfriends clothes

hi! i just wanted to come on here and ask you ladies if you think this is weird or if it’s just me. i’ve been dating my boyfriend for almost a year. my sister has recently been wearing his sweatshirts, shirts and pants that he gave me of his. it has bugged me a little but i don’t want to be dramatic about it. i just think those are clothes that should be just for me to wear when he gives them to me.