Why do sad people make me feel sad?

When my friends are sad or when I people I admire or look up to are sad or cutting, it makes me want to cut like as if its a trend when it shouldn’t be? I’m a sheep. A follower. If my friends jump off a bridge I would too. So I guess when other people tell me they’re cutting it makes me want to cut or feel sad about my life or feel like it should be bad. Even in movies or tv shows if people have shit lives and cut themselves or commit suicide, it makes me feel like my life is shit and it makes me feel like I am relating to them even though sometimes I’m not. So when other people are depressed whether it be in real life or in movies, it makes me feel like that’s the expectation and I blindly follow the miserable trend even when my life is decent at the time. Is it just me?