english isn't my first language so bear with me please. anyways i have had this diagnosis for years now but never looked much into it since i have others too and just thought most of my "symptoms" and irrational thinking stem from them, after looking into bpd and reading alot my whole life makes more sense now and the way i react to things etc

anyways i've always had this issue in relationships that i "overreact" over small things like my partner talking to other girls or leaving me out of plans which makes me feel like they don't actually love me and makes me feel awful but i know these thoughts are irrational so i just eat them up till i can't take it anymore and eventually let it on my partner by disappearing or making them worry. has anyone else experienced this or has any tips on coping before its too late? i really don't like hurting them like this but i can't find a way of coping besides self harm.
would appreciate any kind of tips or advice