Having Soft Stool Or Diarrhea, Took Cap, No Relief. What Medications Can I Take?

Hi! I have soft stool or diahrrea for about a month now. I also have a lot of clear to yellow mucus that comes out every time I go to he bathroom. Stomach tends to cramp often. When this started, I had been given cefuroxamine for a sinus infection on 3/31. I thought loose bowels was a normal symptom. When I finished, within 3-4 days the diahrrea got worse. Ended up going to the dr on 4/16 dehydrated and vey sick. He concluded hat it sounded like I hd C. difficile. Gave me metronidazole . Took 10 days 3x a day. finished that. Improved, but still had soft stool. 4 days after finishing, began running fever ( for a couple of days). Went back to Doc on Wed. a gave a stool sample. Thought I still had the c. diff. Surprisingly, everything came back negative. It was a complete stool panel. Am feeling a little better, but still producing lots of the mucus (tinged with blood). Makes my stomach hurt. All the nurse told me when she called o give me my test results was that I just had diahrrea that got ahead of me. What??? I ve never had anything like his before. I m a 48 year old, other wise healthy female. I eat healthy and exercise. I have gone from 125lbs to 119-120lbs. What could be going on? Any suggestions and how concerned should I be? Thank you.