Does having black and brown thick clots mean a miscarriage?

Last month I have been told by my Doctor that u can try for conceiving and Doctor did follicular study and gave me tablet for multiple egg formation and we tried. But last week when my periods was due, I got this black colour thick clots coming out of my vagina for two days, but there was no fresh blood or bleeding like periods. Does it means that I had miscarriage or some other problem.