If this continues to be a problem try using a sleep medication for a week or two, to help you reset your sleep rhythm. Problems with sleep is common with ptsd. That doesn't mean you have to just accept it. The sooner you can get back on track, the less cascading problems you will experience, imo.
(I, however, have to take a sleep med each night, and even then when I have too much sensory input, I won't fall asleep till early morning hours. )