Whey comes from dairy as far as I am aware (as does casin and most other types of protein filler). Its annoying, I have the same issue. I tried swapping my normal foods over for protein bars or shakes. I lost a little weight but got so ill. I then tried cutting out dairy- and not eating the protein bars/shakes and got better within 2 weeks! (No more mucus, stomach issues, had energy where I had not before and also lost weight!) but as far as protein shakes go, I did try long and hard to find substitutes and turned up a blank.
You could always try making your own, egg whites, soya milk, ground almonds etc just not so sure it would taste great!
