Hi,

It can be very daunting to be told you need to cut out all dairy, especially when if, for you, like many of us, dairy forms a large part of your diet.
I wonder, who diagnosed the allergy? Is there any family history of dairy allergies? What are your baby's symptoms?
It is possible to eat well on a dairy free diet, but you probably need to see a dietician to give you some ideas. It is important for your well being that you are able to eat well.
Formula is made of cows milk, so that won't be suitable. Some babies (around 50% or more) react to soy milk proteins as well. It is important that breastfeeding is preserved while you figure this out.
A related article that explains this is on the ABA website Australian Breastfeeding Association - Lactose intolerance and the breastfed baby
Good luck - let us know how you go