Forgiveness

So I've been having conflicting feelings with a few of my friends. There were stuff that happened this year when they did things that hurt my feelings and really offended me and messed up our friendship. And of course we resolved it and moving on, but for some reason it makes me angry and upset. I'm trying to forgive and let go and move forward, but it's like there is still a negative feeling in my gut. Like how do I let go of my past feelings about that situation and move forward and stop thinking about it? I tried praying about it, but I just can't seem to let go