I Get Diarrhea About Once A Mont But Haven't Had

I get diarrhea about once a mont but haven't had it in almost 3 months since I started a probiotic but today it's back with vengeance it looks like shredded paper and sometimes it's green, yellow, or very dark have had a stool test done but was negetive I think because by time doc seen me it wasn't happening as much what can I do to get relief