Answer:
A six year old does not need details or thorough explanation, but rather reassurance that Mom is okay and that you will get over this and that it isn't his fault. Let him know that you are just feeling very stressed and have a lot on your mind and if it seems that you aren't listening or paying attention when he needs you, that he may need to say "Mommy" a few times and put his arms around you/hug you-this will accomplish several things- it will likely jog you out of the trance and ground you in the present and it will help your 6 year old feel as though there is something he can do to help Mommy while also conveying to him that he is not the cause of your stress/distress and reassure him that you still love and care for him.
I'd go to your regular doctor first and talk to your doctor about this. While it can be dissociation, it could also be a variety of different medical problems. It sounds like it could very well be an "Absence Seizure." Not all seizures cause you to fall down and twitch or yell. During Absence Seizures, you'll just be unresponsive and stare off into space.
http://en.wikipedia.org/wiki/absence_sei...
It could also be insulin/blood sugar related. There are other things that could be going on, but I'd go get checked out health-wise first. If your health checks out OK, then go to a psychologist.