(31F) married and struggling with one specific BPD symptom in particular.

It seems like love and hate are interchangeably entangled in my mind. My heart wants to provide unconditional love for the special people in my life, but I struggle to 'feel' consistently. It's like one second, the switch is off and I absolutely hate that person, even though just moments before, I was fawning and gushing about how amazing they are and how much I love them. 

I am very hot/cold. I can't keep friends. My husband is confused. My doctors are fed up with me. The only people that I don't do this to are my children. In fact, my love for them sometimes triggers my overprotection, hypervigilance, and contempt for everyone else. Mass contempt. I hate you, your mom, your brother, the grocery clerk, people from work, and my own extended family. Most painfully, my husband gets the most of it.

I literally look in the mirror and am like, "fucking stop it. Stop!" and I just can't seem to. 

What are some ways that I can work on not "hating people" so instantly after loving them to death with all my affection? Why do I go from love to hate and have no remorse for anyone who suffers at my emotional hands? 

It's complicated, but thank you for reading and reaching out. I appreciate any advice, tips, tricks, or general support.