bleeding between periods, sign of miscarriae?

Well, yes - a chemical pregnancy or very early pregnancy loss can certainly be one cause of bleeding between periods. If you already had a period and then started spotting around the time of your ovulation, however, it is more likely that you are having an ovulation bleeding. You could also be dealing with a hormonal imbalance, stress, some sort of injury, or even an ovarian cyst or something. Dark spotting indicates old blood though, and I'd say it is quite likely you have an ovulation bleeding on your hands. If it happens again or doesn't stop, still see a doctor.