Hi grateful. Welcome.
Topspin, I sometimes get stuck stewing on what someone said or did, or how I should have reacted to something, and the only thing that really helps is to try to figure out why I was so effected by it. Most irritations don't stick with me beyond the moment, so when they do, trying to figure out what my reaction says about me seems to help me let it go.
As far as the me, me, me thing, no matter how much you give of yourself, you still have to approach the world from within yourself. There's really no escaping it, but it is good to do stuff for the benefit of others.