"Whatever you fight, you strengthen, and what you resist, persists." - Eckhart Tolle.
Forgiveness has nothing to do with the other person, but everything to do with you.
Your body in not designed to hold all that bitterness inside of you.
With you having your muscles tightening up; your breathing being short and shallow; your physical body state being on the defensive; it's not natural.
It might be normal (common) but it's not natural.
This rage you are keeping in will (if you persist in holding on to grudges for long periods) manifest in the form of headaches, aching shoulders, chest pains, back pains, cancers, heart attacks, YOU name it.
The things that you go to the doctor for are caused by your mind.
That is, what you hold on to in your mind, and how awful it makes you feel thinking about them.
You must work on forgiving those that have done you an injustice, in order for you to begin to heal YOUR life.
"Resentment is like drinking poison and waiting for it to kill your enemy." ~ Nelson Mandela