Hi.
Thanks for your query.
Noted the history and understood your concerns.
Diabetes with
Diverticulitis can cause complications and this reduced immunity can cause the flu shot cause flu like symptoms.
Yellow watery poop can be due to either viral or bacterial infection and can be diagnosed by the following ways:
Stool tests for a few consecutive days.
Tests of blood for CBC and particularly for control of diabetes -
hbA1c, blood sugar, getting diabetes under control, probiotics and other symptomatic management.
CT scan may be needed if there is thought of active diverticulitis.
A course of an antibiotic, active against intestinal infection,
metronidazole can helps if there is an evidence of an infection.
Next time when you have to take such shots get diabetes and other conditions under control.