My therapist told me that the personality continues to be formed mostly until around 9-10 (and continues to after the fact) When I was nine I was reeling from the death of my mother. At 11-12 I was reeling from the loss of my stepmother and father.
My identity/personality developed around tragedy, thats why heartbreaks feel like normal to me and happiness or contentment feels like abnormal.
It also explains why I see my heartbreaks that are universal, that everyone experiences, as only ever happening to me. At the time my mom died I was the only one I knew without a mom, and when my stepmom left and my dad stopped interacting with me I was the only one I knew who had just begun recovering from a parent's death and then was hit with a parent's alcoholism at this level. I had learned, at an age that I didn't know any better, that I was the only one who knew pain at this level. I hadn't met anyone who could begin to understand. It makes sense that now, when I am overwhelmed with my bills or my job, that I think no-one else in the world could begin to imagine how bad it feels.
The key for me is I am going to have to un-learn or combat these two erroneous mindsets. Agony is not how life feels like most of the time yet suffering occurs, and I am not the only one who understands suffering, everyone suffers and many suffer worse than I do/have.