I've been there before, you need to start taking probiotics Bio-K plus and Renew Life Ultimate Flora Critical care are two excellent ones. THey will replace the good bacteria in the colon that was lost from the diahrea.
This is important as well it bulks up the stool and absorbs the water in the colon, making the stool easier to pass.
Don't take the sugar free one as it contains aspartame which will worsen your Diahrea.
Cut out the wheat and flour products-many times these cause major problems for us with any colon problems.
Try to eat white rice, chicken breast, fish, bananas,
Lettuce and raw veggies are rough on the bowels-cook your fresh veggies
Is milk and its products a problem-maybe switch to rice milk, soy milk or almond milk all very good.
If eating processed foods elimate them , many fillers and junk are added to these foods. Sugar is also a problem-bacteria in the colon feeds off sugar.
Drink as much water as you can..
Ask your doctor for LOMOTIL it slows down the colon and is much stronger than immodium it works very well.