Does anyone have any advice for dealing with crazy swings in energy level when living with depression?

40-year-old male in the US here. I tend to go through bouts of depression when my job feels unfulfilling or I'm in between jobs, as I am now. Typically I've been able to manage it. But this time something new has popped up... This almost roller coaster tiredness. I'm used to facing an energy drop mid-morning and early afternoon when I'm having a bout of depression. But this time it's different.. I'll just literally feel my energy level drop out from underneath and then if I force myself to power through it comes back, but 15 or 20 minutes later the cycle seems to repeat.