yes foods that we eat can cause black tarry stools. but chocolate donuts cookies don't sound like the cause. thinks like black licorice pepto- bismuth blueberries and iron supplements are more likely suspects for sources of ingested products causing the black-tarry color. the diarrhea and feeling light- headed can go along with the stomach bug. ibuprofen can be harsh to the digestive tract and might cause some internal bleeding. but the shortness of breath is a disturbing symptom when combined with feeling light-headed and having black-tarry diarrhea. this could be a sign of a more significant medical problem and even a medical emergency. conditions such as ulcers gastritis hemorrhoids a stomach tear called mallory-weiss (usually caused by violent coughing") and some types of cancer are legitimate medical concerns. i recommend that you go to the emergency room of a nearby hospital to rule-out any type of internal bleeding that could change from minimal to massive quickly. be prepared for possible testing including barium studies x-rays rectal exam stool specimen culture and a colonoscopy. as you can see by this answer many possible causes may be the reason for your present medical condition. it is virtually impossible to diagnosis the exact cause of your problem through only your question on this web site. since the possibility does exist no matter how remote that you may be in a serious medical crisis please go the hospital (don't hesitate to call 911) where trained medical personnel and testing equipment are available.
i had black diarrhea last p. m. now tarry. light headed and short of breath when standing d face gets pale . i did take ibuprofen occasionally for knee pain past couple weeks i ate several choc cookie night before and choc donuts next day. a stomach bug has gone through my family.