This sounds a lot like hypervigilance; it's not easy, to say the least. So, you've already endured childhood trauma way before this happened. Similar to what Thunder Bow said, this trauma could have echoes from your childhood trauma.
You can't talk about it right now; that's okay. You might not be able to discuss it or anything for a while. When I went through this, I'd talk about my current symptoms and use moments of my traumas as reference (like you'd see in a research paper); so that they weren't the focus. I also started off by talking about trivial crap with my therapist (I was having to rebuild my relationship with her because of a major setback in my personal life). For example, "Those damn Celtics let me down, again to the ****ing Lakers" or "My job sucks". None of this stuff really mattered too much to me, but it was easier to discuss and help me get out of "lock down" mode.
Healing from trauma takes time, go at your own pace. Don't be too hard on yourself.