I think you have PTSD or known as Post Traumatic Stress Disorder. It mostly comes from what you've seen and experienced in war. This is all in your brain, many soldiers that i've known have joined small groups where they talk out loud about what they've seen. Some go to psychologists to get a better insight. This is not a disorder you can fix normally with medicine. It takes time, patience, and people. It's always better to say it outloud. Good luck.