AU and headcanon of Snape trying to improve his mental health.
Snape getting a watch that has alarms set for meals.
Snape having a magical poster board hanging on his wall with reminders that eight hours sleep is medically preferred and to shower at least twice a week.
Snape writing down good things on the arm that doesn’t have the Dark Mark so he can pull back his sleeve and remind himself of them. His arm being covered in things like ‘Albus,’ ‘an article I wrote appeared in a magazine,’ ‘the new Defense master tripped on a trick stair,’ and ‘no students blew up their cauldrons this week.’
Snape making an effort to be more involved with the other staff at Hogwarts. He feels completely ridiculous interjecting into conversations, and at first he just thinks he’s intruding and he feels incredibly awkward. But eventually, it starts getting easier, and he finds he likes most of the staff members.
Snape making an effort to do better while teaching, he takes deep breaths to control his temper and tries very hard not to raise his voice and just explain mistakes and how to fix them. The students spend the day staring at him like he’s gone crazy and they all speculate that maybe he’s actually someone else polyjuiced to look like Snape.
It takes him a while to find a balance and be stern and firm without being irrational and yelling, but teaching becomes much more rewarding once he does.
He reads that trying new things can improve your mood. He tries out wearing the occasional color with his black clothes. It makes him feel like there’s a spotlight on him for awhile, but he decides that he likes dark purple.
Snape feeling good when he wakes up and still feeling good when he goes to bed that night. He can’t remember ever having one full day where he felt good, and he makes sure to write the accomplishment on his arm.
When he tells Dumbledore about all these things, the Headmaster tears up. He tells Snape that he’s proud of him and so pleased to hear that he’s getting better. He wraps Snape in a hug and the Professor is able to return the embrace, to feel proud of himself too.
Some days, he still can’t fight back the depression. Some weeks, he still struggles to take care of himself. But he’s getting better and that’s the main thing. When he feels like he’s failing, that’s what he tells himself, that’s what Albus reminds him. His problems don’t just go away, but he’s learning how to cope.