Guilt, like any other feeling, is yet another emotion that affects us. Indulging in it is avoidable if we can learn to step back and watch them. It may sound like an improbable proposition given the environment of the modern society. Feelings like thoughts continuously come and go - it is for us which we let go and what we harbor.
My personal experience of dealing with lingering negative emotions is limited to mindfulness meditation practice and support of healthy friends. Others can try and decide if it helps them.
Thanks for raising an important question that is hardly ever discussed openly, despite its widespread nature.