How much does your friend know about your mental health issues, e.g. PTSD? Does she know the ways in which they affect you? To those who have not experienced mental illness, it can be difficult to understand how PTSD can affect one's interactions, and that your responses during a problematic episode do not signify a lack of caring. Maybe she perceives "PTSD" and "dissociation" as vague words, and does not understand the depth of how they affect you. Good luck.