Parenting, in my opinion, is for life, not just for Christmas (so to speak). Family is part of us, and should be, for life. Even if we live apart, the support/love should be unconditional, but, sometimes, when they are unsure how to cope, it may come across as abandenment, but it is just they do not have the knowledge to cope themselves. It may be you need to try and explain to us what you see as rejection and what actions they do that make you feel this.
Some of us do experience, what is known as poor parenting and I think this can happen throughout adult life too. The relationship does change though and it does become a bit more distant than it was in childhood, which is not poor parenting, it is just respecting we are now adults. Not sure of your situation, at the moment, and at what stage of adulthood you are at.
Self harm is from distress of some kind, not sure where your core distress comes from. Is part of your stress actually coming from your family? As your 'name' you use on here says, excessive stress needs releasing. What is important here is to find a more healthy way to release it, if this is possible. Do you have support from services at mo?
Feeling we are not worth it can come from many different experiences, and self-hate is something that is in need to work on improving. Trying to love ourselves can change the way we see everything else around us. Loving ourselves can be the hardest thing though, but it is important to try and not focus on what we can't do and have a go at focusing on what we can and what our strengths are. CBT is a Therapy that may help with this.
I hope this helps xxxx