Black foul smelling loose stool (not tarry) w/ stomach pain minutes after eating (no nausea/vomitting). Gastric bleeding? Will it likely heal on its own?

U need to be checked. You may be right--melenic stool is blood originating from the stomach. Lots of things cause dark-color to stool (see my earlier healthtap answers on the subject), but the possibility that you may be hemorrhaging requires immediate medical attention. Don't wait for this to "heal on its own"--it may worsen instead.