I've been having diarrhea since last week, and i cut off all the junk food and trying to eat healthy and drinking lots of water, but with no luck?

Stop all food: except for simple carbohydrates like rice,potatoes,bread,toast,crackers. Only eat if hungry. You need to hydrate up to where you are making urine. A week of diarrhea could be bacterial,and you should see your physician for stool studies for blood,WBC’s,C.diff test, and stool cultures to rule out Salmonella/Shigella/Camphlobactr. If still unclear of diagnosis,consult with GI.Have u been out of US?