I'm of the opinion that some anger is good for us because it prevents us from making the same mistakes over and over again. If I had never gotten angry at my X I would have continued to sit in my house and cry about it all. If I had not become angry about what he was trying to do to me and his children, X would have taken everything we had both worked 17 years for. If I had not become angry with him, I would never have started to protect myself from him.
The anger fades FL, and eventually it goes away. But that's only after we've taken care of business and give it enough time. If we don't do that, we sometimes retain that anger forever.
What matters IS how we deal with our anger. We can choose to have a good attitude regardless of what happens or we can choose to go through the rest of our lives with bad ones. It's entirely up to us.
It does go in cycles though and I applaud your telling the truth here about how you feel. That's key. You're saying it here where it will do no harm.