What would you do?

Shortly after losing my dad, I lost a baby at 21 weeks and it was the most devastating experience of my life. We were just starting to tell people I was pregnant so only our close friends and family knew. After it happened it, my mother started telling everyone she talked to. I asked her not to, explaining how this was my story to tell, but now a year later she continues to inform people... my third grade teacher she ran into, my father's side of the family and the random person at Ross. She literary tells everyone my life story even when I ask her not to. Every time I feel like it's a betrayal and it not only upsets me because I'm more private but because it also forces me to relive the experience when people want to talk about it. She's very self involved and I feel like rather than mothering me, she owns me. Like anything that happens to me good or bad is really about her. What should I do? How do you set boundaries with someone that doesn't respect them?