my friend couldn't keep my secret

so during may, I broke up w my boyfriend. but I regretted it, basic breakup sht. I told my trusted best friend from my new squad, cuz I trusted her. she was proud of me breaking up w him. and as I said, I regretted breaking up w him, normal breakup stage. told her it, knew that she wouldn't tell him. right? she told him. she literally told him. I trusted her with all my heart. my trust issues are already cooked, and she's roasting it. now he's confronting to me about it and I don't know what to say.