I used to get depressed quite a bit. I would shut down, and get lost in some work. This sometimes meant not showering or taking care of myself for a few days.

I used to get depressed quite a bit. I would shut down, and get lost in some work. This sometimes meant not showering or taking care of myself for a few days. Although over the years I've given up on seeking external motivations, and this has helped me mitigate depressive episodes. Everything we'd ever need is within our own minds. The ancient Stoic philosophers had a lot to say about this. Read their words, perhaps when you're not feeling depressed, so that you can remember them during these moments. But it's probably beneficial to get professional help, as @NoZebra120vClip suggested.