I don't really have experiences similar to yours, nor am I any type of qualified "diagnoser" (as proven by my use of the term diagnoser ). But as I was reading it it does sound very ptsd from what I know of it. For people suffering from ptsd, triggers can make them feel like they are re-living the event. If you scroll down on the main forum page, there is a forum for ptsd. I've never been there personally but they might have more insights for you, or information about it.

As far as googling, everyone experiences things differently. Ptsd is mostly publicized about war veterans. But that doesn't mean someone who was in a house fire doesn't have it or that you might not. I know it would probably be helpful to find something that directly relates to your situation, but I would look at the symptoms in other cases and see if yours are similar.

Your best bet is probably to talk to your therapist about it. Have you told him/her about the incident with your son and how it triggered emotions for you? He/she may not have experience with ptsd but I'm sure if you agree that it needs to be looked into you can be referred to someone who does. I've heard really good things about emdr therapy for ptsd.

Here are two links I found that seem to offer a general overview of the symptoms. Hope they help
http://www.cmha.ca/bins/content_page.asp?cid=3-94-97
http://helpguide.org/mental/post_tra..._treatment.htm