Letting go of anger is difficult. Two things: try to compartmentalize it in a place in your mind reserved only for negative thoughts. Don't ignore the feelings, just put them in a mind-space that does not require you to ruminate about or act upon.

R elatedly, my mindfulness practice discusses RAIN - Recognize the negative feelings, be Aware that you are having bad feelings, Investigate them with a in a spirit of curiosity "Where does this come from?" How am letting these feeling affect me and my relationships?" and finally, do Not over-identify with those feelings. That's the crux. Emotions come and go (although some stick around longer than others) but they do not have to define you or your relationships with others unless you let them. "Its just a feeling, it will pass." Eventually, your synapses will rewire themselves and the feelings won't be a salient as they are now. Good luck.