[ Psychology ] Open Question : Is this a mental disease?

[ Psychology ] Open Question : Is this a mental disease?

So I believe there's something wrong with me, I can't put what it is into
good word but I will try to make sense of it. I feel like if someone else
has something that i had it makes me want them dead, really angry in other
words. It's not just that, here's a story that might explain it, this girl
I know wants me to tell her boyfriend about a secret but I'm not going to
do it because if she was using me I wouldn't know, I just get really
skeptical of if someone gets something that I either had or have :/ I
don't understand