What does this type of discharge mean?

Sorry for the strange comparison however I haven't had a period in over a month (usual for me to go without for months, very irregular). Today I had discharge appear that was small in amount but that of the consistency of melted chocolate definitely brown in color and no red to it at all? I absolutely hate comparing with chocolate but honestly that's exactly what it resembles. Anyone had this or know what it means? I have taken ovulation tests and pregnancy test about two days ago (both negative).
Thanks and blessings to everyone