What were the antibiotics you were on ?
Are you on any acid suppressants like Prevacid?
The black stool could be related to upper GI bleeds as a result of stress erosions/ ulcers in the stomach. So , you sgould start on acid suppressants for that- Pantoprazole 40 mgs daily for 10 days would calm it down.
Please also get your stool tested. The cause of this diarrhoea needs to be elicitated. It could be antibiotic related pseudo membranous colitis also.
Apart from this, you need to keep yourself hydrated with plenty of electrolyte solutions/ Gatorade, to replenish the loss.
Information is for EDUCATION only. Doesn't replace a visit to your Doc. Positive feedback appreciated.
Immodium should not be used in infective diarrhoea / dysentery.
You should go to the emergency , if this does nt subside soon.
As , I suggested , you would need to go for a stool test to rule out antibiotic associated colitis. If this is detected, then treatment regimen is different , and would need to be started immediately.