Cassiopeia's experience has been mine, as well. I am currently re-reading an extremely insightful and helpful book, of which, was recommended to me, by my therapist, titled; The Body Keeps The Score - Brain, Mind and Body in the Healing of Trauma, by Bessel van der Kolk, M.D., of which you might find of value. It has helped me, profoundly. With regard to your inquiry about alternative methods, among other information, the book offers various, natural methods of treatment for symptoms of PTSD and anxiety, including insomnia, recurring nightmares, headaches and other symptoms.
Some other modalities that have benefited me, are, Magnesium, practicing yoga, meditation and immersing myself in nature, as often as possible.
I've tried valerian root and melatonin, of which caused me to experience intense, vivid dreams, and made me quite groggy the following day, but I know a few people who have found significant relief of sleep disruption, as the result of taking these particular, natural remedies.
I hope you find relief, and feel well, soon.