Dealing with PTSD after witnessing a car accident

I have a list of mental illnesses. and my ptsd is one of them that hasn't really been triggered lately. accept thus past Sunday. I was going on a wall with my s/o when I heard a skid and then a crash I take off running take my slides off and run faster to the scene of an accident white van crashed against a concrete pole. red car front end obliterated, grey suv two women mother and daughter I'm utter shock but alive. red car owner comes to me screaming I know he's mad at the situation and not me I'm on the phone with 911 operator tells me they got 2 other calls in about the same accident and to let her know when emergency vehicles arrive 3 cops, a ems, a fire truck all arrive to the scene. I'm standing still but my ankles are shaking on their own and so are my hands and my gut is tight. my s/o finally shows up and I collapse into their arms just howling screaming crying. I was in shock. this was the 2nd time about 6 years later 2nd accident I've been close to the 1st one didn't affect me this bad and now i can't stop thinking about it my anxiety random fluctuates and I can't go near the spot it happened even tho I live right around the corner from it.