hi. i have also struggled with that and variations at different points in my life. it makes things very confusing for sure.

i would have to say for myself that i know i am NOT dissociated when things don't feel like a dream, when i feel more in my body, more connected with my body and the world around me both in a physical sense and also emotional at times.

a 'normal' dissociative state would be like being in class and daydreaming or drifting off in a scenario in your head. most people do that at some point out of boredom or other things.

derealization and/or depersonalization are types of dissociation that are on a more moderate to severe level (depending on how long it lasts and how much it affects your functioning) and are generally the feeling of things around you being unreal, a dream, not feeling like you are in your body or only in part of your body (instead of your whole body, maybe you feel like you are just in your head), or you cannot feel your body or things feel far away, etc.

do you see a therapist? do you notice any particular situations, emotions, triggers, etc. that cause it to happen more than other times? have you tried any type of grounding techniques to see if that can help?