Mirroring Soggy, a break from active learning isn’t a death sentence for your progress, passive enjoyment of Japanese content without explicitly studying grammar/vocab/etc will maintain all of your hard work while giving you some much-needed mental rest. But first and foremost, above all learning goals, is taking care of your mind and body – please don’t push yourself during this time. I know the depression instinct is to beat yourself up over long breaks and paused progress, but please be so patient with yourself 
Japanese will be here when you feel better, as will we!
(btw happy cake day!)