Whump idea: antidepressant withdrawal.
It comes with a bunch of nasty symptoms like nausea, dizziness, brain zaps, body aches, flu-like symptoms etc *and* worsens the mental health issues that those meds are treating in the first place.
Bonus points if the whumpee forgets to take their meds due to some sort of crisis or conflict and have to deal with withdrawal on top of that.













