
From someone with BPD and rejection sensitivity, my best advice is to write down rants in your notes app or in a journal. Personally, handwriting calms me down. I also try to think back on other small things that ruined my day in the past, and either I can’t remember anything noteworthy or if I do, I see in hindsight that it wasn’t that serious.
And maybe it would help with you even though it just makes me more upset, but my partner will try to logically talk through the situation with me. That might work for some, I just used to be extremely irrational and only wanted validation in the moment. But the things I just mentioned in my first comment have helped me reform my thinking and I’m a lot less rigid and more open to change and disappointment.