Neal drops the now-empty bag, cognizant of the fact that he should pick it up, but also too distracted by:

A) How good that tasted and how much better it must taste fresh.
B) How much he can still smell/hear/see/feel.
C) The fact that he just about inhaled a bag of blood.

“Oh god,” is what he says, and jolts over to the empty sink to retch into it without actually throwing up. His body, it seems, is unwilling to give sustenance up to nausea at the moment.