Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
1
Is any of this happening now?
Call 911
Seek urgent or emergency help for:
Severe or rapidly increasing abdominal pain
A markedly swollen or firm abdomen
Fainting, confusion, or unusual drowsiness
Very little or no urine
Breathing difficulty or signs of shock, such as cold, clammy skin
Heavy rectal bleeding
Inability to pass stool or gas with pain and swelling
Other emergency signs, for anyone
Someone who is struggling to breathe, gasping, choking, or cannot get words out
Someone who has chest pain, tightness or pressure lasting more than a few minutes
Someone who has sudden weakness or drooping on one side of the face or body, slurred speech, or sudden confusion
Someone who is unconscious, or cannot be woken
Someone who is bleeding heavily and it will not stop with firm pressure
Someone who has had a seizure that will not stop, or does not wake up afterwards
Someone who has lips or skin that look pale, blue, grey or blotchy
Someone who you believe has taken an overdose or swallowed something poisonous
2
Is any of this happening?
Be seen today
Contact a healthcare professional promptly if you develop frequent watery diarrhea during or after antibiotic treatment, especially if it continues for more than a short period.
Also seek advice if you have a previous history of C. diff and similar symptoms return.
Arrange prompt medical assessment for diarrhea accompanied by fever, worsening cramps, reduced urination, or difficulty keeping fluids down.
These symptoms do not confirm a complication, but they need urgent assessment.
Every sign above is quoted from the sofidex article on Pseudomembranous colitis. If you are not sure, err upward — it is always reasonable to be checked.