Mom telling everyone I’m fat

So random older people are texting me giving unsolicited advice because I’ve been married for 5 years and still no kids. My mom had been telling them that I’m fat that’s why I can’t get pregnant. She talks to then through facebook messenger (she recently learned how to use facebook and had been connecting with long lost friends and relatives). I’m 38 and been ttc for 3 years. Had one chemical this year. I think I’m gonna explode. I’m so upset. I’m 4’ 11” and 129 lbs. I know that’s a bit chubby but telling it to my face hurts so bad. Specially from aunts whom I’ve never seen for years and even a grade school teacher! I want to confront my mom but our relationship isn’t the best. I just recently started having her in my life again and I don’t want to ruin that. Short back story, she left us few years ago and just reconnected and is living with my sister now. Just heart broken and wants to vent out. Thanks for anyone who reads this.