Hi thanks for asking question.
Your stomach pain history is acute sudden presentation.
Do you have eaten any outside food??
As you might have simple gastric infection by outside food.
If you have eaten excess with fast food then it might be gastric
indigestion.
Here i will advise you to take
omeprazole and one prophylactic antibiotic like
ofloxacin with
ornidazole combination.
Meanwhile follow below instruction
-Take more water
-More green leafy veg salad for few days
-Avoid high fatty diet for 3 to 5 days
-Avoid smoking and alcohol
-Fruits taken more
-Avoid excess spicy food
-Avoid excess tea and coffe
Get your stool examination just to be sure that it is not
parasitic infection.If stool showing eggs or trophozoites then treated accordingly.
All fats are digested by stomach.So excess fat also can lead mucus discharge.So avoid fatty diet for few days.
If still no benefit then USG or Endoscopy done after consulting ER.
I hope your concern is solved.
Wish you good health.
Dr.Parth