Unprotected intercourse several times in the course of a month but took the emergency i-pill 6-7 times that month. Period got delayed by 7 days. Trace mounts of blood (mostly red but darker sometimes. It was light once) with few clots have appeared every now and then for the past 4 days. The quantity of blood was very little in the beginning and has increased very slightly now. It is still not continuous. Took a pregnancy test in the morning but it said negative. Could it be a false negative? Usually have regular period. Is this implantation spotting or irregular period due to hormonal imbalance?