Sudden problem with cow's milk

[rallytog1]

My 8mo has taken to food really well. However, she seems to have a massive problem with any food made with cow's milk - the entire contents of her stomach are projectile-vomited 1-2 hours after eating anything made with cow's milk.

The weird thing is she's been ff since 3 weeks, so I would have thought any milk intolerance or allergy would have become apparent before we got this far. It seems to be pure, fresh cow's milk that's the issue.

I'm not sure what, if anything, I'm meant to do about it - take her to the doctor, HV, or just hope it's a passing thing and she grows out of it. Just wondered if anyone has any experience of similar and if so, what you did and what the outcome was?