Hi,
Welcome to the ehealthforum and I am glad to help you out. The mid cyclic spotting can be due to implantation bleeding or spotting can also occur midcycle at ovulation. High level of stress, cholesterol, hormonal imbalance, chain smoking, and dramatic changes in your life style may be some of the common causes of your symptoms.
If this was the first episode of such midcycle spotting, then wait for the coming cycle and try lifestyle modification by reducing stress and decreasing cholesterol levels. But if the repeat happens, then please consult a gynecologist and get yourself thoroughly examined to diagnose the cause.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care.