BB, sorry about this situation. One thing is for sure, you will find out once and for all how good a friend she really is. If she is as good as you thought, you can expect an apology for her reaction (sneering?....really). Thus, one danger in 'coming out.' Almost 50 years ago in college, I revealed my bisexuality with someone I thought was a friend. His reaction was similar and he even went so far as to 'spread the word' around to mutual acquaintances. I have been fearful, closetted and latent ever since, although unfulfilled. That has been a secret source of distress all of my adult life. I know you are distressed about the possibility of losing your best friend, but if she doesn't come back, apologize and make up you are better off without her. Best wishes.