Brief Answer:
Ulcer flare up may not.

Detailed Answer:
Hi.
Thanks for your query.

Read and understood your query.
It looks that you have/had gastric/duodenal ulcer. Such ulcer can not cause pale colored fluffy stools, double ordinary amount, excess belching, passing of excess gas, and reduction of appetite.
Stress can add-om the existing problems.

The most probable cause of the symptoms you have mentioned looks to be befitting into enteritis.
I would advise to have stool test for 3 consecutive days and get appropriate antibiotic, metronidazole, probiotics, activated charcoal tablets, any medicine to relieve the stress and whichever your Doctor would advise you on clinical evaluation, examination and investigations.

I hope this answers your query.
Please feel free to ask for further relevant queries if you need to or if you feel that there is a gap of communication.

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