Hi thanks for posting your query on health care magic

The stomach ache which you, have from last 3 days following drinking and eating spicy tacos, along with diarrhea is due to gastritis (inflammation of stomach)
Drinking and eating spicy food, can produce gastritis.
Diarrhea could be due to infective process, which may have occurred along with the food.
However you have not mentioned the colour of the blood.
Was it bright red or dark tarry?
If it was dark tarry, then it could be due to bleed from stomach, as part of gastritis,
However if the blood was fresh and bright red, it could be due to bleeding in your anorectal
area,may be due to straining on stool or due to some local pathology in the anorectal area

Hope I answered your question.

Hello!

Thank you for the query.

Yes it can be bleeding peptic ulcer. Especially if the blood in stool is dark. But such symptoms can be also caused by pancreas disease (as you have mentioned about drinking and spicy foods) or bacterial infection. Blood in stool if bright or red can be caused by hemorrhoids, polyps or other large intestine diseases.
As you can see many serious diseases can cause such symptoms. That is why you should not wait anymore and visit your doctor. You should have abdominal ultrasound, full blood work with liver tests (AST,ALT,GGTP), pancreas tests (amylase). Upper GI endoscopy should be performed as soon as possible if your hemoglobin level is low. If not, you should get scheduled for this test. If the blood in stool is not dark, colonoscopy should be performed.

Hope this will help.
Regards.