My dad committed suicide

My dad took his own life 4 days ago and I'm the one that found him. My friend told me to see a therapist right away and I was able to go the day after and she told me I have PTSD from what happened. I'm not sure what to expect emotionally right now. I'm sad that my dad did this and I'm grieving him but I'm also finding myself getting so angry over things that never would have bothered me before. I guess I just don't know if this is normal? Should I expect to be angry at everything randomly? How do I even begin to navigate this?