Email text size suddenly very small uncontrolled font change

Without warning, the text of incoming emails is suddenly very small.  The body of text is crowded into the left side of the screen.  And, old emails in the inbox are exhibiting the same behavior.  If you double tap the text, it resizes to fill the screen, but you shouldn't have to double tap every message to get it to read properly.  I have tried accessibility function and increased the font size, but that has not helped.  Reading email in landscape helps.   I recently turned on iCloud but then turned it off with respect to emails.  Cannot figure out why this is suddenly happening.   Help.