Came out to my sister (MTF trans)

It wasn't entirely unexpected. I'd been mulling it over for a few weeks, and had made plans to hang out with her and tell her. I'd anticipated a lengthy conversation, and instead, I sat dead silent on that porch for an unknown amount of time, sick to my stomach, almost unable to speak or move. (She was great and gave me all the time I needed to collect myself) I had an ominous feeling as though my life had just ended, one still lurking in the back of my mind. Nothing more was said on the matter, and she drove me home. If it was that terrifying with my most understanding family member, I can't begin to imagine doing this song and dance over and over again. I am absolutely numb right now and have no idea where to go from here.