Honey, this reaction is completely normal. I actually have a similar situation with someone who occasionally rides my bus. I get angry and afraid every time I see him, and it's completely out of my control. A good thing that might help is, if you can, look at him closely and pick out the things that are different. Make sure that he knows what's going on, and make sure he knows about habits or phrases that remind you of that other person. See if he can help you get through the visual memory so that it doesn't affect you as much anymore. Please, let me know if it helps, too. I would love to know that I was able to help someone.