The ocean in a dream tends to represent emotion on a scale bigger than you can fully hold -- its vastness makes it a fitting image for feelings that stretch past ordinary awareness. Calm water can reflect emotional ease, while a churning sea often names a feeling that's grown larger than you expected it to.
Three manner of wayes the Planets are varied or changed, by reason of their first qualities, of their Houses, and significations. - William Lilly (1602.-1681.)