There is a direct relationship between nightmares, insomnia, and problems with memory (as you may be able to imagine). Do you know what the root of your nightmares may be? Do you suffer from PTSD or some type of experience which may not have been traumatic but enough to cause trouble with sleep? There is specific medication to treat nightmares but I think you would want to first verify that your sleep disturbance truly is that of nightmares and not some other form of disorder while asleep. For that matter you should also consider getting blood work done to be sure metabolically you are intact which sometimes can cause or contribute to symptoms as you re describing. If you d like to work with me on a private consultative basis then, please write me at bit.ly/drdariushsaghafi and we can go from there into more detail and try and determine what would be the best course of action for you.