Hi welcome to Health care magic forum.
Thanks for choosing H.C.M.F.
As you describe your self and 2 kids were taking vegetable juice containing, parsley, spinach, cucumbers, capsicum, carrot, and beets since 4.5 months.
You are alone facing
abdominal pain,
bloating,
nausea, in spite of omiting one vegetable per day, but no symptoms to children and nosymptoms to you when you eat same vegetables.
I am not clear whether you have tried with out cucumber juice.
Any how what ever the reason, is omit the juice comletely, if still the problem is continuing after few days, you must be having some problem with your stomach.
If that happens i advise you to
consult a gastroenterologist for diagnosis and treatment. you may need to have gastroscopy done besides other routine tests for confirmation.
wishing for a quick and complete recovery.
Best regards.