Afraid to Breastfeed in Public

I stopped using bottles and am exclusively breastfeeding. I don't know why but I'm afraid/nervous to breastfeed in public. I'm so afraid that someone is going to say something and I can't use a cover because every time I do, my LO gets covered in sweat. (He's a big baby, 9lbs 6oz at birth.) Any words of encouragement? Also, my sister has a choir concert at her school tomorrow. Do you think it's too much to breastfeed there? I mean, if my baby has to eat I'm obviously going to feed him. I'm just so nervous! The farthest I've gotten is breastfeeding my baby in the Walmart parking lot 😭😭😭