Up to 17% of U.S. Vietnam War Veterans and U.S. Iraq War Veterans have combat-related PTSD (post traumatic stress disorder) (Richardson et al., 2010). So roughly 1/5th of soldiers will get PTSD after being exposed to combat.
If you have PTSD, then there is help available. You can obtain further self-help with Anxiety Protocol- Anxiety Self-Help Book, and KalmPro- Anxiety Natural Supplement.
Reference:
Prevalence estimates of combat-related post-traumatic stress disorder: critical review. Richardson LK, Frueh BC, Acierno R. Aust N Z J Psychiatry. 2010 Jan;44(1):4-19.