Dreams, indeed, can bring glimpses and memories from past lives. It is said that time does not exist in other dimensions as it does here on earth and that the past-present-future happens simultaneously. But I digress...
Your singing and tennis playing dreams, Nancy, don't sound to me like past lives. They mirror your on-going waking life desires of being appreciated for your gifts and talents. There is a feeling of competition within you as you often compare yourself to others (or they to you).
You DO have shining talents. You simply would like it if this were noticed and appreciated. Maybe, too, you would like to prove this to someone in your life.
All of your dreams have been building to a crescendo, Nancy. Your time...is now.