Drowning in a dream typically reflects being emotionally overwhelmed -- more demands, feelings, or responsibilities than you feel able to keep your head above. The specific moment you struggle for air can point to exactly where the overwhelm is coming from, whether it's work, a relationship, or an internal pressure you've placed on yourself.
When either Taurus or Libra ascend in women's nativities, and Mars therein, the native will be immodest and unchaste; the same if Capricorn shall ascend. - William Lilly (1602.-1681.)