For moms with babies that have allergies!!

My daughter has a milk and soy protien allergy. I am breastfeeding her and it's been a bit over 2 weeks since I have completely cut out dairy and soy. (No dairy since the start of December but only cut soy 2 weeks ago). The doctor said it would take 2 weeks to get out of her system. She is still having symptoms (specifically very mucusy poop).

Do you think it is likely that she is allergic to something else as well?

Or is this still just from the soy?

Also we are waiting on a referal to an allergist for allergy testing. What do they do for an allergy test for a 4 month old??