even though i would never suggest stopping breastfeeding this early, i know that most babies this young would be pretty upset if you stopped cold turkey, i would suggest a slow weaning.
just because you are leaving for four days doesnt mean that you have to stop breastfeeding completely. if you just wean him down to one or two feedings a day that would not be too many to pump. they say it is best to breastfeed at the very bare minimum six months, but i love it when the doc says a year!
you could still breastfeed when you come back from your trip because the milk doesnt always go away immediately, sometimes it takes a long time for it to dry up. i have even heard of someone who was still lactating after her kids were teenagers, and she never even pumped or anything! bodies can be weird like that.
good luck, i really hope you find the solution that works best for you and your baby!