Long period of spotting?

Firstly, I feel GREAT! but I've been spotting for over a week now. I missed my period January and I still haven't gotten my period to this day in February ever since December. I'm extremely healthy and I have been checked for pregnancy and std/infection and am negative of everything (that I was checked for). What can this mean? Can this be common? Could this be a "new period" where my blood is lighter and lasts much  longer? I'm very curious and hesitant to go to the doctor just yet...