Even though upset feelings are very uncomfortable, it's okay to have them Right in this moment you don't need to say anything to him or get past it. All you have to do in this moment is find a self-supportive way to help you ride out the emotional rollercoaster. That's all you have to do. By the time it is time to meet with him again your feelings will be in a different place to where they are right in this minute and you can address those feelings then. All you have to do now is ride this out and wait this out. Even the stuck part will be easier to think about once the emotional storm calms down.
You're getting through this okay. Just keep riding out this storm, it is going to pass.