I'm sorry that's happening. It is a difficult situation to experience. Acceptance is a process and a non-linear one, but it's awesome that you're going to the gym. Working out, moving your body, it'll help you not internalize the trauma. So many other benefits like keeping depression and anxiety down. Good for you for finding a way to cope!
RE: GRIEVING after the DEATH of a LOVED ONE: what will help and hurt you