What Causes Loose, Mushy And Stringy Stools?

I have had a change in my stools for about 4 months now, very loose and mushy, an orangish yellowish color. My doctor ordered a stool test. I brought it home and as I was taking some samples of my stool and putting it in the jar they gave me, I noticed some strange like hairs or threads in my stool. what could that be?