What would be causing loose thin stools?

I am 39 years old female. Last year i had a colonoscopy done which they found one polyp and removed it. But for about 4 months now i have been haveing altenating loose, thin stools, or diahera and one day i had mucus in my stool. I am very stressed about this and a natural worrier. I have been to my doctors about this and he is booking me to see a specialist.Can anyone give me some info on different causes of this. Would it be bowel cancer???Or IBS or something different.