Symptoms are nightmares triggers from flashing lights, loud slams, complete darkness I have had flashbacks that felt like a panic attack but also fla?

PTSD. I understand your distress. It is likely that you had nightmares due to Traumatic experience with feelings of fear, panic, anxiety, overwhelmed, helpless, sad and angry. Any of these feelings need to be taken care of, resolved and help you in your healing. Panic attack and nightmares can be treated successfully. See Psychiatrist for Diagnosis, Therapy and Medication.
Possible PTSD? Nightmares with additional features of hypervigilance, anxiety, and fear should be managed by a psychologist or psychiatrist who can prescribe specific medication for the nightmares (Prazosin). Good luck.
Anxiety symptoms. It sounds as though you’re suffering terribly. Please seek an evaluation with a mental health provider where some treatment options can be implemented and where your symptoms can become more manageable for you. Usually, this would be more effective through both therapy and medications. Good luck!
Therapy? Have you yet tried any form of psychotherapy? Typically, the optimal combination of things to treat emotional issues such as anxiety or depression is medication (which, on your best day, is supposed to take the edge off symptoms) but the real gruntwork takes place in psychotherapist's consulting room.
Few things. Triggers are important pieces to recognize as they help with understanding of events bringing on more complete realization. This incorporated into either Cognitive Behavioral Therapy (CBT), Hypnotism, Meditation-from simple focus to just be-ing. Medications may play a part in the process also. A Clinical Psychologist or License Clinical Social Worker(LCSW) would be place to start.
These symptoms are. consistent with severe anxiety of the panic or PTSD varieties. When did this start? Have you had trauma? Consult with a psychiatrist for possible meds, but also with a psychologist specializing in treating trauma. Some sources say EMDR helps, others don't, so shop around. Meanwhile, learn meditation and/or yoga and practice good sleep habits (so some research on this).
PTSD? I would want to evaluate for trauma. Flashbacks from specific triggers would indicate a possibility of a history of one or more traumatic events.
Nightmares. If your nightmares and flashbacks are occurring after some trauma, I developed an original theory, Planned Dream Intervention, that helps people learn how to sleep peacefully through their dreams. Everyone I have taught this to, when their nightmares stopped their flash backs stopped. Both were intrusions of unresolved trauma. But consider a good physical exam also to rule out organic disorder.