Dissociation is better known as zoning out. Everyone dissociates to some point which is normal like daydreaming on a long stretch of highway where there is no traffic and you don't hardly recall how the whole trip to your destination. Or spacing out at a boring meeting or class.

But dissociation can happen to people who have survived trauma or abuse where they loose time like they zone out for hours especially when faced with something that upsets them. There is also DID or Dissociation disorders which is a more extreme form of dissociation where people have multiple personalities or alters, some get amnesia, move to another town and live as someone else not knowing.

I'm copying some things from another post someone wrote to me. Hopefully will answer your question. Don't worry just cuz your T said you dissociate; doesn't automatically mean a person has DID.