Spontanios Anger Destroying Relationship

about 95 percent of the time i am a happy & relaxed person but occasionally something small will flip the trigger inside me & i become another person, i cant think clearly, i become arrogant & can not put myself in the shoes of others, the usual scenario is a huge temper tantrume during which i have no control whatsoever of my emotions, resulting in me saying really aweful things to my partner or someone else close to me & making a fool of myself at the same time. after the anger is released i go back to normal but the damage to my relationship cant always be reveresed, ive been trying to control myself for years but i just cant, ive been diagnosed with ADHD but i dont take medication because its not healthy, could my problem also be hormonal? or do i have a borderline personality disorder? does anyone else have this problem? its almost like i have 2 personalities & one of them is really evil... help me im a psycho when im angry, & i dont want to hurt my boyfreind anymore