I was never diagnosed with BPD, but a therapist for dyspraxia and general conditions related to autism in children theorized I did have it, and suggested I look into it with a further therapist or professional (which I never did, as I'm personally not too sure if I have it or not, it also seems BPD carries a pretty big stigma sadly).
I don't have every symptom, however I do have perception issues. I often question if what people say about me is true. I also question if they ever say anything that's intending to hurt me, although in recent years I'd say I've gained better at that. On mood swings, I've always had those, I find one small thing can often ruin a brilliant day.
I have always had issues with all kinds of relationships though, be they platonic or romantic. I remember as a child I was always paranoid my parents would die somehow, and I remember once having a huge fight with my sister as she thought it'd be hilarious to joke that my parents _had_ died (I was around 6 at the time and she was in her 20s, needless to say I am delighted she is no longer in my life). If my mom or dad ever came home slightly late I'd flip out.
I remember in school if certain friends didn't attend school the days would be awful and lonely. I'd usually have just one or two friends and never deviate from them. As I grew older I had to deal with many cases of unrequited love. And of course, it all connected into my autism, social anxiety and maladaptive daydreaming.
It was at it's worst in my mid teens. I had a few crushes which were awful, before finally a disastrous several year LDR. Before going into a slightly better, but still exhausting one a few years later. Both times the relationships failed due to me, although with the second one, we thankfully managed to end it on a nice note, and slowly phase it out which hurt neither of us, and we've since became good friends again. I do still value them a lot, but they're no longer my "world", and I don't have an almost fanatical desire to "serve" them.
BPD from my experience was mainly loving someone so intensely it just drives you insane and you can't focus on anything else. You get a single track mind. You don't even eat or bathe, as you space out so much your mind just goes on endlessly, and hours disappear out of days. I'm glad as I've grown older I've gotten much better at dealing with this. If I do have BPD, I feel I have at least managed to conquer it to some degree.