Killing the moose was of course wrong. It has affected you badly which is a good thing. It means that you realize what you did was wrong. You could be having a spiritual awakening. This might sound silly but, in your mind say you are sorry to the moose. Ask for forgiveness. Then say thank you. You have to let go at some point. You are a better person now.

You can also campaign against hunting. That way you will save many animals and feel great.