Get through today. If holding onto those feelings helps you accomplish your mission for the day, do it. If forgiving those people helps you accomplish your mission for the day, do it. Set today’s mission. Plan what’s necessary to accomplish that mission. Then execute.
For me, I could spend a lot of time reliving the traumas of my 20’s or my childhood (admittedly not as bad as what some people deal with) but none of those feelings help me accomplish my mission. Get through today. Get to the next day. Hope the next day has better opportunities.