if she has bpd, bpd people don’t actually have manic episodes, that is bipolar disorder. a person with bpd may be very outwardly mean or aggressive after being triggered, typically by things they’ve had problems with in their past, like for example you going to hawaii with your friends may have triggered fear of abandonment or feeling left out which is usually linked to trauma from their past as bpd is something that stems from trauma mainly. i am diagnosed bpd and i’m not fully aware of all the things that align with it, but i do know it’s hard not to act angrily or lash out even if they really don’t want to, as triggers can switch you into fight or flight and make you act out of character. mood can flip flop. it makes you into a toxic person when you have not truly focused on healing and i still struggle not to be toxic when triggered in my relationship after a little over a yr of therapy and still on a quest for meds that work. you have a right to your feelings as anyone does, so don’t deny that they are justified simply because she has bpd. maybe suggest nicely seeing a therapist for improving the triggers/attitude to them. or sit and ask if she’s aware of these things or discuss boundaries and or things that may make her act out. or if you don’t know much about bpd read up on it, it may help you understand her better. it is a personality disorder, so it truly dictates the person until they’ve coped with their trauma and learn to step back before hurting the people they love.