Lightning in a dream often marks a sudden flash of insight -- a realization that arrives all at once rather than through gradual thought, and can feel as startling as it is clarifying. Being struck by it may reflect a shock that's reordered your priorities, a revelation you can't unsee once it's happened.
Retrograde Planets degenerate from their proper nature, by that means Fortunes are made Infortunes, and the evil Planets far worse. - William Lilly (1602.-1681.)