here in the USA they make the distinction between ....

Believing

vs

Feeling

oneself is not real.

Believing oneself is not real is called psychosis and delusional beliefs. the reason behind it is if you were not real you would not be on this earth physically. you have a physical, tangible body, someone can touch you, someone has to say excuse me in order to get by you if you are standing in their way, physically you exist. therefore when one ....believes... they are not real, its called being out of touch with reality, having delusions, hallucinations, delusional thoughts\belief depending upon which terms the treatment provider is using.

where as someone who ......feels.....like they are not real but knows they are real, that they do have a physical body, that they do exist, they just ..........feel........ disconnected from their self thats called many things like dissociation, depersonalization, depersonalization\derealization disorders. the reason its called this is because here in the USA reality testing remains intact. a person knows whats real and what isnt, a person know they really exist, they just ....feel ....like they dont.

my suggestion is to continue going according to what your own treatment providers are calling it. since they feel this is delusions in you thats a good thing because medication can help you to feel better. it may take some time and a few different meds to find the right ones but it will happen.