My udd is now 32yo but it started from a very early age. udd cried a lot as a baby. Always a very sensitive moody child who could literally cry all day but could never say what was actually say what was wrong.
That sounds familiar. I didn't live with my adult BPD stepdaughter until she was college-age, so I didn't experience her upbringing, but her dad tells me she was a very fussy child. As she grew into young adult, your description rings true: very sensitive, moody . . . but could never say what was wrong . . . and then she'd seem to make up stories to fit her feelings. She had seemingly unending needs; sometimes I felt I was living with a newborn! Geesh, I couldn't even enjoy a weekend away with my husband, without having to cut it short and run back home early because of the pwBPD's crisis du jour.
Like your daughter, I suspect my stepdaughter might have been bullied at school sometimes, but then again, ever since I started living with her, it became clear to me that SHE was the bully. My sense was that she felt aggrieved by others when no offense was even intended. She held grudges and blew things way out of proportion. Worse, she'd react by lashing out, making HER the bully. You see, when she spoke about her so-called friends bullying her, she left out important details, such as her role in instigating a conflict, which I'd sometimes learn about much later. The sad result was that she lost all her friends, even her bestie from middle school. She was alienated from every last family member, making an exception for her dad and me, only because she needed a place to live.
I understand some of the regret, because bending over backwards for the adult child with BPD usually means making sacrifices in your own life, and attention away from the other kids who are behaving. It becomes a perverse family dynamic, where bad behavior is rewarded with attention, money and resources, and good behavior gets leftovers. I too feel some resentment--the holidays marred by meltdowns, cancelled/interrupted vacations, messy living quarters, huge financial strain, marital strife, living as if in a passive-aggressive war zone--which probably could have been completely avoided if she'd just leave (and not be allowed back in the house). Even when she's not around, my heart stops every time the phone rings at night, bracing myself for some bad news.
It's not easy for a parent to let her go and do whatever she wants, because she is suffering, and parents want to help. The thing is, I think the parents do all the trying, when the pwBPD, if untreated, has basically given up. So parental efforts to "fix" and "save" her are doomed to fail. The irony is, my stepdaughter insists all the time that she's an adult, she can do whatever she wants, and I want to say, FINE, you do that (and don't come to me asking for more money or help). But in her world, her incentives are all mixed up. She makes the decisions, but her dad bears any adverse consequences. That has to stop, or we'll be destroyed, because an untreated pwBPD knows no limits. We have to be the ones with limits (boundaries).