Kiya - while my system could never be termed "normal" I do get this pretty frequently, several times a year I think. I've never really put it down to stress before, you may be on to something there. I discussed it with my doctor years ago but I do not recall exactly what the explanation is, but it is "normal." There are times when I've only had this and it's been a 'mini' period with a real one following a couple of weeks later.

I would bring it up the next time you go in to see your doctor though.