Numb
This isn't real.
Dawn is used to things not real, things never happening.
She never screamed at Mom for leaving Dad and moving to Sunnydale.
She never blackmailed Buffy about Angel coming to her window.
She never spent all summer worried sick about her sister.
She never saw snow.
She was never held hostage by Faith.
NONE OF THIS HAPPENED.
So logically, she never found Tara cold in a pool of blood.
She never pleaded for her to get up.
She never spent hours banging her own head against the wall, trying to wake up.
No.
No.
No.
Not happening.