I'm also reactive, but have few PTSD symptoms left. One thing that I've realized about myself is that I'm more sensitive than other people, and because of this I tend to have stronger reactions to things. The thing that I notice most of all when I have a strong reaction is that I'm immediately critical of myself (probably because I was criticized so much as a child for having strong reactions). What helps me the most with this is to give myself time to accept my strong reaction before I do anything. This means not doing things like trying to justify getting so upset, but just acknowledging that I am upset, and that I'm having the feelings that I'm having. Doing this can require having a bit a space from other people so I can sit down and talk to myself. But I notice that the more insecure I am about my own reaction, or the more I assume that others will see my reaction as inappropriate the more I react, and try to justify how I react. Try giving yourself time to have the feelings, its ok to be sensitive and feel things deeply, you don't need to justify that to anyone.