Stopped drinking milk?

My nearly 15 month old (who loves her milk and has lots) usually has two bottles of milk a day and for a week now she’s been unwell with a virus but she had still been having lots of milk as usual. Then she started to not finish the bottles but she was happy with it. And now she’s recovering well and nearly better but for the past 3 days she hasn’t had her milk? She will start drinking like normal but then spit it out and get really stressed and upset and the she tries again to have more and the same thing happens and she starts screaming and then refuses the bottle and she’s very hard to calm down. I’ve tried a cup because I thought maybe she was ready to give up the bottles but that didn’t work. she hasn’t drank more than a couple of ounces in a bottle these days and I’m so confused and I don’t understand why she’s doing this? Does anyone know? I’m obviously giving her lots more milk/yogurt/cheese in her food so I’m not too worried but I just want to know what’s going on