It sounds like the term you're describing is resentment. I can relate.

We are all sufferring tragedies in life. For whatever reason, some people seem to have more resources than others.

It is hard. I have not yet figured out how to let go ~ but I do know that for my own health, I need to do it. Because holding onto the past only brings me down more.

Many people find religion very helpful to them in this process. Other people find that time helps. Some never let go of the past. I wish that there were a fourth category! lol...

(((hugs))) to you!