it's also just reasonable to get a little depressed sometimes. It's not always obvious in the moment what is causing it - if anything.
At my company we try and remember that we and our colleagues are not bottomless motivation machines. we have highs and lows, and it's best to recognize when you're in a low and adjust your own expectations and those of the people around you. 

 Yeah,that’s what I have. Kinda like a little depressed about nothing but it keeps me demotivated