** trigger warning for denial, SI **
This all seems so surreal. But I know it has to be real. At least a part of it.
Imagined parts don't force you to believe it is real/DID.

And they don't trigger with everything that is harmful (knifes, bridges, heavy objects).
They don't want you to commit suicide (I was able to prevent it every time so far; and discover ways of coping along the way, I don't think I'm in serious danger).
They don't scare you.
They don't disagree and make you comply (nothing harmful).
They don't tell you to take care of yourself (and thus them).
They... don't mimic your parents in a bad way (introject?).
It is not normal to have intrusive thoughts. --edit: to the point they can't be blocked.
It has to be a sign I dropped out of college.
It has to be a sign I can't keep going to things I want to go to.
They don't make poems for you when you don't want to do it and hate the person it is for.
It is not normal to be really afraid of the dark at this age (19).
It is not normal to behave completely different in different situations, without any control over it.
It is not normal to not be able to talk about DID/DDNOS, but still be able to write about it.
And still I keep denying it.
An imagined disorder doesn't have such confusion with it.
An imagined disorder doesn't have all of the above.
An imagined disorder doesn't have denial with it.
Why can't I accept it?
Do I need a formal diagnosis?
Do I need a therapist that confirms the existence of alters?
I don't know. And that's the whole problem. I can't make sure this is either not real or real.
-- edits
It are no imagined friend when you want them to not nag you. Imagined friends don't do that.
It aren't imagined friends when they make you do things.
It is not normal to be (a bit) social one moment, and NOT ABLE TO BE SOCIAL another moment, without really knowing why.
It is not normal to be able to talk to someone like there's nothing wrong, but at the same time disliking that person, WITHOUT ACTING. And other times not being able to 'fake' it.
--
With 'normal' I mean neurotypical, someone without any (dissociative) disorder; the average person.