Quote 43
I stumble down the hall […] till I find my very own door and slop inside and throw the lock, not even bothering to turn on the lights, just falling falling a mile downhill to the bottom of my brown chair, where I can sink my teeth into […] my wrist and cry like the baby I am. (54.11)
This is Melinda after she gets the horrible we're-not-friends Valentine from Heather. Melinda stays true to her pattern. When she's sad she isolates herself and inflicts pain on herself.
Quote 44
It's like smelling the perfect Christmas feast and having the door slammed in your face, leaving you there in the cold. (85.1)
This is Melinda after she tells Rachel that Andy raped her and Rachel doesn't believe her. Melinda thought she'd feel so much better after telling Rachel, but Rachel doesn't react the way Melinda wants. Still, Melinda sounds slightly less sad than normal here as if telling does give her some relief.
Quote 45
[…] WHAMMO! – a thought slams into my head: I don't want to hang out in my little hidy-hole anymore. (88.1)
Here, near the end of the novel, we see Melinda waking up, moving away from sadness. Sadness is a useful emotion for her, but she's ready to feel it less than she has been.