Been recently diagnosed(ish) with borderline personality disorder and wanted to know...?

why i cant handle change, like my best friend - whom iv got the "i hate you dont leave me" realationship with and who im attached to was blatently being careful around me like shes a harsh in you face kind of charectar and she NEVER apologises and im used to that and ever since an incident last year when her sister and her sisters bff whom i also live with in student accomodation started to bully me and caused me a mental breakdown of the worst kind that iv ever had she's been proper careful and like stepping on egg shells around me and i HATE it. i feel suicidal and reckless just thiking about it, im proper freaking out about it and i know i shouldn't be worried or anything i just dont know why i do this? im panicking and really feel like going sick at her and just shutting myself off again. idk, why but i can never handle change how ever little i mean lets face it its no biggie but im still flipping out, im becomming really paranoid, depressed, angry and panicy and i really really really do not want to talk to her. i feel so suicidal and reckless right now, literally want to od. i also wanted to know if the symptoms seem to get worse before u start ur periods because i seem to become really depressed and unstable during that time? please help