Milk allergy??

Emily • 27, married to my high school sweetheart. One daughter, 9/12/13. One angel baby, 8/11/15.
I think my 17 m/o dd has developed a milk allergy. From what I have researched so far, late onset milk allergy isn't very common, but it does happen. It seems like every time she drinks milk, she has incredibly runny stool. She has also vomited two huge amounts of chunky milk in the last month. So, I'm thinking about not giving her whole milk for a while. Do any of you give your 1 year old something other than whole milk? What do you give them? (DD hasn't had breast milk since she a week before she was 12 months. She self-weaned.)