What do you do to motivate yourself through hard times? I will not promote.

Not sure where to start. I’ve been at it for 18 months, 4 months ago I went through a pretty nasty cofounder breakup after spending most of our time and money developing a product no one wanted, and the few who did were people I just did not want to build a product for. So I laid off all but one engineer to reduce burn rate while we figure something else out. At the beginning of the year we pivoted to something I think people will use, but I took two weeks off for my wedding, and now that I’m coming back to it I have zero motivation to work on it. Just thinking about it drains me. All this rambling to ask the titular question: how do I pull myself out of the pit of despair?