In the first 30-60 days following the incident, there are many expected responses that are normal reactions to an abnormal event.
When a traumatic event overwhelms our normal coping mechanisms, it can impact all of our body-mind systems (hormonal, enzymatic, neurological, circulatory, etc.). A sense of disconnection (feeling dazed, numb, detached), agitation (crying, screaming, feeling physically jumpy or restless), anxiety (sleeplessness, poor concentration, irritability, intrusive images, etc.), and feelings of guilt may occur.
In the longer-term, some of these may intermittently arise but reduce in their frequency and intensity. To the degree any of these symptoms interfere with your daily life, relationships or work, seeking professional mental health assessment/treatment is strongly advised.