Movies are tough...they are one of my biggest triggers and completely unpredictable. For me it's gotten to the point where avoidance is really the only and best option, even seeing a movie theater can set me on edge. Unfortunately all I can recommend is having someone very knowledgeable and trusting screen what you watch, or just avoiding things that are "too real" such as live actions movies and tv shows. Avoiding something too realistic can really help, and has been a huge boon to me. You're not alone though, and it's a tough problem :/ I really hope you can find a way to make it easier on yourself!