Getting emotionally attached to people too easily
I've had this problem for a while and it's gotten even worse. Any person I meet at some sort of 1 off event and I 'click' with them/ they show me some sort of affection, I start to get clingy towards them. Even worse, sometimes I obsess over them even though I'll probably never see them again, and can feel depressed, lonely and anxious for days on end about it.
E.g The first time I met my brother's girlfriend, after 3 days of her staying with me and my brother, I immediately developed some sort of attachment towards her and haven't been able to get rid of it since. As soon as she left, I felt lonely and depressed the following days again. I do weird things like keep mementos to remind me of the people I met and got attached to. With her, I kept smelling this t-shirt of mine I let her borrow once she had gone, because the scent of her perfume was still on there.
Long story short, the other day she said for certain she wants to move abroad and emigrate (likely permanently), regardless of whether my brother choses to move with her.
This has had me feeling extremely down these past days, I haven't even known her for a year, I don't understand why I care so much (I've not exactly fallen for her or anything, I want her to be with my brother, I've just developed a strong attachment) . I'm paranoid and extremely anxious she'll break up with my brother because he won't move with her, emigrate and I'll never see her again. I'm worrying about their relationship like it's my parents getting a divorce or something
Sorry for the long wall of text, this has never left my thoughts this past week, I needed to let it out somewhere. I've been sad and felt really low simply over this, makes me feel like I'm really not normal, anyone else had similar experiences to getting attached to people quickly? I feel kind of stupid. i'm 18, my brother is 29, his girlfriend is 26 btw