Brief Answer:
Food poiosoning causing inflammed gastric mucosa.

Detailed Answer:
Hi,
Have noted all your details,

Most likely it's due to gasroenteritis because of food poisoning .Infectious organisms or their toxins can contaminate food at any point.Our gut consists of its own environment of micro organism called gut flora(Good bacterias).They are responsible for proper digestion of food.Once this flora is depleted by toxins released by bacteria causes symptoms like bloating belching vomiting loose stools etc Leading to inflammation of gastrointestinal tract clinically termed as Gastroenteritis.
A short term course of antibiotics can be considered if stools are postive for bacterial or protozoal infection(As prescribed by your Gastroenterologist)
Apart from that would suggest you to take a good probiotic for 3 days. This will help the good bacteria's to replenish again. Once the flora is replenished intestinal motility and secretions will be improved.Take plenty of water.For controlling pain antispasmodic like Dicyclomine can be taken twice daily along with Nexium40mg twice daily(For relief in gas and burping).
Drink plenty of water and electrolytes,Weakness is due to Electrolyte lost in stools.

Thanks

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Brief Answer:
Follow up answer.

Detailed Answer:
Hi,
Before starting antibiotics Get a stool routine and microscopy test done.In case there is a bacterial or protozoal infection antibiotics would be started otherwise there is no need to give antibiotics.
Just follow other instructions,Usually its self limiting and will settle down in 4-5 days.
If vitals blood pressure and pulse is normal,You can follow above given suggestions for 2-3days before consulting doctor.
Regards and Good luck.

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