The figurative language is personification.
The meaning behind this quote and use of figurative language is rich. It means that "we" (those that are speaking) suffered slowly during said draught, and time continued passing while the days blended together. By 'day after day the pitiless sun blazed down,' the narrator means that every time a day passed and the sun set, it was sad and pathetic - meaning so little. The sun is personified in order to add depth and information to the text, which allows the reader to grasp the idea and mood the author is trying to convey to the audience.
