I agree with Blueberry that as you start to notice when and why you dissociate you can gain some control over it. For example, do you know why you dissociated when you were scanning documents? Where you thinking about something else that caused you distress or did it have to do with the task you were doing (maybe feeling like you weren't doing it right or something along those lines)?
In my case I started to catch myself starting to dissociate and then brought myself back so I can see what is making me fearful and consider whether I need to be afraid, what I can do about it, and so on. I actually don't dissociate much if at all anymore.
If you figure out what is causing it and whether you can move through the distress it gives you more control and power. There are lots of books available nowadays that help you to move away from dissociation to being present so you may want to try one. Also, if you have a therapist you can let them know and they most likely can help you with recognizing when you're dissociating and how to bring yourself back.
Just my thoughts of course but I hope they help!
In my case I started to catch myself starting to dissociate and then brought myself back so I can see what is making me fearful and consider whether I need to be afraid, what I can do about it, and so on. I actually don't dissociate much if at all anymore.
If you figure out what is causing it and whether you can move through the distress it gives you more control and power. There are lots of books available nowadays that help you to move away from dissociation to being present so you may want to try one. Also, if you have a therapist you can let them know and they most likely can help you with recognizing when you're dissociating and how to bring yourself back.
Just my thoughts of course but I hope they help!