I just want help

At 12 diagnosed with “bpd tendencies” but I’m pretty sure it’s full blown at this point. My relationship of 4 years has been a whirlwind. I can’t be out in public with my boyfriend because i fear that him being attracted to other people will somehow effect our relationship. Today we went to go disc golfing and saw women doing yoga in the park. I was already uneasy and then a woman on a bike made me uncomfortable, we were leaving when I also saw a really good looking woman and that’s where it turned for the worse. I started throwing a tantrum and I then got out of the car and ran off without my phone so he didn’t know where I was. We eventually found each other and went home. I feel like I can’t compare to literally any other woman. They are all intimidating and I feel like I don’t belong in this reality. I have severe trust issues with my boyfriend and my family. He tells me I’m the most beautiful person he knows. He tells me CONSTANTLY how much he loves me and wants to see me be happy. And I know, in reality, it’s human nature to find people attractive but I can’t cope with it, or accept it. I really hate the way I look, and act, and sound. I hate what’s happened in my life and I feel so far down and I’m trying to climb up this dirt hole but every time I make it up so far, there’s just an avalanche of dirt that pours back onto me and suffocates me until I feel nothing. Then I reset and it happens again. I don’t want to live this way anymore. I can’t seem to get ahold of myself and understand my worth, and love myself. I feel so ashamed of even being alive sometimes knowing that both my parents were 14 when i was conceived.