My doctor diagnosed me with this when i was 16. When you have bpd you feel like your never good enough, no matter what people say, you still feel like you aren't good enough. Being in a relationship is hard because the thought of being left is always there, and its not the normal fear, its a nagging, buzzing "feeling" in your brain that eats at you all the time. People with bpd have a real fear of abandonment so being clingy is a BIG problem. Impulsivity is a real problem, it's never the same behaviors with any two people but mine are spending money, sex, and reckless driving when i get upset or angry. Difficulty controlling anger is a bad symptom, it drives alot of people away from you if you are unfortunate enough to have that symptom. Another bad one is feeling empty all the time, like you have nothing to really live for. The worst though is recurrent suicidal behavior, or threatening to do it.
I hope you figure this out soon and honestly I hope you have been misdiagnosed. Good luck.