Breast milk has high levels of lactose in it so I would highly doubt that it is LI. I have a severly lactose intolerant bub, and the LI is generally symptomatic of bloating, diahorreah which really stinks (trust me!!!) and occasionally vomitting. She could not tolerate breast milk. I recommend taking her to the dr and seeing if they can order skin pri ck testing to test for cows milk protein allergy.

Try a soy yoghurt if she is reacting to cows milk bases. And keep BFing as long as possible, she is getting adequate calcium from you, plus all the other added benefits of breast milk.