I was resently dyognosed with PTSD after 6 years of suffering. i am 13 and my T was pretty rubbish at telling me about the disorder all i really know is what is implyed in the name, please could you tell me about what i need to know?

the cause of the PTSD was my friends death ( i wacht her been stabbed 3 times in the stumach and saw her neck been slitt) when i was 7.