Not accepting a bipolar diagnosis is extremely common, especially when a person is in a situation like the OP where she feels she can't share it with those closest to her. Even if you're in a situation like my own, where family and friends alike are 99% supportive, to say nothing of gracious (and even curious) about my illness, it's STILL hard to accept. It changes your life forever. It changes your self-image too. You can know a thing inside for years, even if you choose not to acknowledge its existence openly; once that word is written on a piece of paper or entered into a medical record with your name on it, it becomes real. And that's hard to handle.