My bf only 3-month old used to scream a lot b4 i cut out dairy. her poos are always gelatinous, like jelly. could she have an allergy?

Sounds normal: Breast fed baby poop is often gelatinous - this sounds completely normal. The only baby stools I freak about are rock hard/formed, pure white, dark black or red/bloody. The different colors of yellow-green-brown-orange are all normal and watery to seedy to jelly-like all normal types of consistency. If gaining weight well, not to worry about her poos - they sound normal.

Baby poo and milk: I don't believe it is allergy. Infants with food allergy typically get eczma or bloody stools not jelly in the stool. If you are not using dairy, you are on soy. Best to be on digested formulae like alimentim or neutramagin. Try either and see if the stool becomes normal. The jelly stools likely represent constipation typically seen in soy fed babies.