Ok well the good news is you are still alive and have survived, so serious kudos to you. The other (I think, just stick with me here) good news is that your mind has a natural defense mechanism built. The way this works is that when something traumatic happens your mind chooses for you, to ...how do I explain this. It's like taking a deck of cards that's always been in order from Ace to 10 but your mind takes those cards during trauma, throws them up in the air, messes up the order, and now your mind is taking certain pieces together but in fragments. It distances you from the trauma, and allows you to process it in pieces. So first piece is you almost died. Second piece is you are alive. Pieces in between connecting the two are distanced, those cards are under the table, lets say. Your mind likes to blurry those edges between live and die so the almost died piece doesn't seem so alarming. It's still alarming to you but not as much if you were to process this perfectly, with all the lines of thinking being linear, and clear with a beginning an end.
Ok so now what. What do you do? It's hard to feel like you are not in control but you are with future actions only. It's perfect that you're seeing a therapist about this. The more you talk about it + time = healing and you will align all those cards piece by piece until you feel whole, complete, and in line with reality.
Now in a spiritual sense, I don't want to discredit you here. I do think there is a highly spiritual message that you could learn from this, and I'm a believer in things happening for reasons. You can find those reasons only and really really only towards the end of your journey.
I have been through multiple trauma during different periods of my life, I self analyze too much, but at least I have the confidence to know exactly what I'm talking about.
Now, another thing before I take off here - I hope you are seeing someone who specializes in trauma because those are the only people (TRUST me on this) who truly understand what you are going through and will be able to explain everything so it's natural for you to understand, and this will help tremendously in the process.
In the meantime you can do some self help that I had learned with my trauma specialists. These are small steps that add up to bigger relief and grounding, and what you need right now is to feel grounded in reality.
When you feel out of your body like this try the following (of course adding your own version to the general gist of what I'll list) :
Take a hot bath, and as you do notice what you're feeling. Feel your legs and toes with your hands as you say to yourself something along the lines of "I am here, I am alive, and I am well. I know this because I can feel my body and my reality = my experience. This is my experience, I know I'm alive because I can feel my legs, the heat in the bathtub, I look around and I'm in the same place I was 2 minutes ago, there is constance."
Find text/numbers/signs around you you can read, and read each letter backwards (that way your mind doesn't try to read, this is only logic here), while moving your feet so you feel it rubbing against the ground. Remind yourself "I am here, now". It won't work immediately but it'll eventually catch up to you.
Just think of this as, when someone is physically injured due to a car crash one goes through physical therapy. Well you went through emotional trauma so you need emotional and physical therapy. The two are connected, the body and mind.
Mindfulness Meditation - I have a page I built that has a ton of exercises and they truly truly truly help I cannot stress this enough. Here's the page :
http://protopage.com/rosiecocoJust know that even time, is relative to our experience. That's actually a scientific query which I agree with you can look up. Time to get your logical mind in gear, as this will be the glue that holds together your sense of reality. As long as time is relative to your experience, then so is everything relative to your experience. Your experience will always be more than valid. You're alive because you believe you're alive. You weren't meant to go, otherwise you would've. You deserve the life you were given, and life would want you to be all in, in the now.