How do you know the difference between antibiotic side effects and colitis?

So antibiotics can cause stomach cramps and loose stool which are also the symptoms of antibiotic induced colitis.

I have been having these symptoms for about three days now and have been off my antibiotic for three days now. How do I know when it could be a sign of something much worse like colitis?

Tagged as: antibiotic induced colitis, antibiotics, loose stool, stomach cramps