How do i stop caring too much? (15F)

I'm and intj, and they're known for being straightforward. And that's one thing I've always wanted. But I can't seem to, because I feel like people are gonna hate me, I'm gonna ruin our friendship. Like, I can't even tell people that I feel uncomfortable, because I care too much about them.

So how do I stop? I'm stuck in a horrible situation with someone who I used to consider my close friend, and I just want to tell him that he makes me uncomfortable, and that he should stop. But everything I say seems too harsh, or too laidback.