What Treatment Is Suggested For Diarrhea?

I have had diahrea for a week now. I have been eating only white rice and bananas. At first I had like worm shaped stool then like soft lumps, small. Now I am having just liquid, thick like cream of wheat. it seemed to be slowing down, but yesterday got tired of just rice so I opened a can of chicken noodle soup and added quite a bit of rice to it. Shouldn t have I guess because I was awake all nite with very loose stool and quite a lot of it on the first time. Then I took 2 immodium at 1 oclock a.m. and then l more at 3 a.m and another one at 6 am. I can only take 4 in a 24 hour period according to the instructions. So far I have not had a bowel movement and it is now 7:42 p.m. Hopefully it has stopped, but if not can I start taking immodium again? I have a prescription from the Dr. to take a stool sample, but instructions say that I have to quite taking anti-diahreal medicine 5 days before I take the test. How can I do that and still take immodium for the diahrea if it starts up again? Is there anything else I can do to stop it?