I take it this is red blood? Which if so, is coming from the lower part of the GI tract (large bowel or rectum).
If dark blood, this indicates blood that has been digested.
If there is more than a tablespoon, and with your stomach hurting, I would be seen tonight to find out the exact cause. Other wise, there are too many possibilities and without an in person evaluation, would be impossible to narrow down.
directly above the navel in the upper middle section of the abdomen — is where you might feel pain associated with stomach disorders. Persistent pain in this area may also signal a problem with your upper small intestine (duodenum), pancreas or gallbladder.
Heartburn/GERD
Peptic ulcer
Hiatal hernia
Hope this helps Hun