They kept saying they just don't understand and I don't know how to help them understand.
Ayesha...I, too, am sorry that you had to experience the traumatic events and now deal with family members who don't understand. I'm sorry that every single one of us in this forum has a reason to "seek refuge" here.
I can't tell you what to do, but I can share my own experience with this issue, because that's all the wisdom I have.
I no longer believe that it is my responsibility to help anyone else understand, ever. This may not work for other people, but it's where I am right now, so it's working for me. My stance is this: If you love me, and genuinely care about supporting me, then you need to educate yourself about PTSD. I answer questions that people have, but I reject ignorance-driven negativity at every turn. And the people in my world who choose to heap their insensitive criticism on top of the wounds that I am working very hard to heal rather than educate themselves, then I do not allow them into my inner world. I acknowledge their presence, but that is all of the access I grant them. And I draw that very hard line because I have learned that I can't help someone else to understand, especially when they don't really want to know.
So, I don't have a lot of warm and fuzzy advice on this issue, as I have chosen to draw hard lines out of self preservation. Perhaps one day I will feel differently, but until then, I'm not wasting even one iota of my time on trying to help anyone else understand me, what I've gone through, or why I can't just "forgive and forget" so that I can "move on," even if it means that they are no longer a part of my life. That's me.
I understand that your family is very important to you, and that you want them to be a part of your life, so I really do hope that you find something that helps you to do so :)
Blessings for your journey!