I've had times where I've come and gone from poker for months even a year or so at times. In past few months I've changed my game up, started actually winning/getting in the black and so want to play even more. But even now some days i just don't want to play so I wait until that desire to play is there and I play.
Just go with the feeling. If you want to play, play. If you feel tired of it, unmotivated, then don't. Really think about how you feel when you sit down for a session, if you find yourself bored, angry, tired, disinterested, etc, just leave the game. If it's a tourney, then focus on it and just don't reg for any others that day.