I've had cramping for 2 weeks than one day of heavy period than spotting the next. what does this mean?

Normal variation: Normal variant or natural expulsion of nonviable product of conception.

Period variation: Cramping for "two weeks" may be related to several issues, so more information is necessary to give a complete answer. If pregnancy is possible, it may happen with miscarriage. Also, a large clot may block the cervical canal and stop bleeding, and when the clot breaks up, the blocked bleeding is released and seems overly "heavy".