The most complex phenomena I deal with, trauma is dependent on how fully your nervous system was functioning beforehand. Even something that doesn’t seem as though it should be that big, really can be, if you were compensating before a traumatic event happened. Moreover, much is dependent on what happened WHEN the trauma happened: higher carbon dioxide levels in your system, for instance, can layer even more difficulties on how well you compensate. Were you able to move and react, or did your body tell you to deal with it by freezing? Again, huge differences result in that. The chemicals that the body generates from the experience can get stuck in the body, and determining both where that is, and how to move it off, can make the difference between healing and staying trapped where you are.
Trauma therapy really needs two parts: the cognitive, generally talk therapy from a therapist, as well as the somatic, where the chemicals in your body can trap your being. If you understand the trauma but can’t move past it, generally it’s that you need to move those chemicals out of your body. What a relief!