Hiding in a dream commonly points to self-protection -- an instinct to stay small or unseen while something feels too exposed or shameful to face directly. It can reflect a real situation where you're holding back a part of yourself, waiting until it feels safer to be fully visible again.
The Moon doth then most especially transfer actions unto the inferiour world, and the influence of other Stars, from whom she is separated when she is swift in motion. - William Lilly (1602.-1681.)