As long as there's no blood in your stool, it's OK to try to manage diarrhea at home for a few days.
Start by changing your diet. Avoid all spicy foods and dairy products. Or, try the BRATT diet, which limits you to bananas, rice, apples or applesauce, weak tea and toast. It may be boring, but it can put your stomach on the right track after just a day or two.