Why Nighttime is a Trigger

So when the sun sets, my anxiety sets in. This has happened since I was raped while I was sleeping. And, then my nieghbor was shot at night, and the next night she was found. But, what I hadn't realized is that night is also the time when my father would come home from work and become abusive with my mom, my sis and me. So, no wonder its such a serious trigger for anxiety and PTSD!