To dream that you are a lesbian, even though you are straight in your waking life, represents embracing every aspect of yourself. It is symbolic of self-love, self-worth, and passion. You are at ease with your sexuality and femininity. If you despise lesbianism in your dream, this means you are afraid to explore your sexuality.
If you are a lesbian in your waking life, then the dream is simply mimicry of who you really are.