My eldest dd was also breast-fed and had a terrible time with colic and constantly gorging/sicking-up everything. My wife heard there was a strong chance dd could be dairy milk intolerant and that the proteins pass into breast milk. She moved off cow's milk for the remainder of breast-feeding and saw a massive improvement.
Here in the UK there's many, many alternatives to try: soya, oat, almond, rice... (Goat's milk was a little too "goaty" for our liking...) Hopefully you've got some alternatives available to you, too. Try it for a week or two; if you see no improvement, you've not lost much but tried anyway.
Good luck and keep loving your little family. They deserve all your time and love, just like you will earn theirs back ten-fold.