So sad; such pain.
"was it a dream?..." this stanza is very strong. This girl, you, have sharp perception and potent insight.
"what's buried deep taunts the heart" like a "zombie" that needs re-killing each time "... Vivid memory" breathes new life into it. "...vivid memory," so vampiric, forces focus on the heart of the "undead" matter at hand as each "stab of consciousness" re-opens "...ancient stitches" and life-force is drained away.
Beautiful, if biting and bitter imagery throughout this poem.
I'm sorry for her loss...