I know you can become allergic to anything at any point in time. It stinks, but you can find out wether you are lactose intolerant or if you have a milk protein allergy by going to your doctor. If you are just lactose intolerant, there are a variety of milk options with dairy removed, including ice cream and even yogurt! If you have a dairy protein allergy, unfortunately you have to avoid all cow dairy products. However, there are a ton of new options on the market now!