Welcome to PC!
My suffering is really all over the place. Like you, I have a hard time connecting to people on a superficial level, which makes it hard for me to get close to people. On an intimate level, it's not hard for me at all. The problem with my interpersonal relationships is that I get attached way too fast, either platonically or romantically. That causes me to become paranoid when they don't text back, and then I get delusional, and then I get angry, which leads to me giving them ultimatums, i.e "if you don't pay more attention to me then I'll cut you out of my life forever!" I also have a habit of impulsive spending and black and white thinking.
I get lonely easily too. I enjoy solitude, but sometimes I just feel so alone. And it's this aching loneliness too, this horrible aching that won't go away unless someone gives me attention. It's terrible. To deal with that, I began cutting. I've been clean for several weeks now, and I hope to never have to resort to SI ever again.
I was never given an official BPD diagnosis due to my age, but it's pretty obvious I have very severe BPD traits. I first came to this conclusion when I fell in love with someone back in January. My emotional instability became worse. I became paranoid. I even threatened to commit suicide. Over one person. That's kinda what lead me to do more research, because I've never heard of attachment issues being a part of depression.
Now, I'm doing okay. I'm stable, school starts in less than a week, and dance will also begin. I find that doing something to occupy my mind helps with my emotions and my loneliness. I like to knit and read, but you can do whatever makes you feel comfortable. Medication helps. I just wish I could find something that would dumb them down a bit, however.
Having a close circle of friends helps. I've maybe 4 or 5 close friends that I can rely on, and all of them have been friends with me for more than a decade. Some find that being alone is better than being with people. Others don't. What matters is that you don't attach your self-worth to how much they like you.
Hope this helped.