Have you read The Poker Mindset by Matthew Hilger? It's a good book. There's a whole chapter on downswings.

If your play has been affected or your br is threatened, moving down for awhile is totally fine/standard. Downswings can also be a good time to take a break from playing, maybe look in your database or do a little studying. But don't change your game just because of the runbad, that could make things worse. Try to be objective in assessing your play. As Hilger puts it, poker is short term luck and long term skill.