For a couple of months now I’ve noticed that every time I get my period it’s is around 5 days to a week early. It just keeps jumping to an earlier date every month. Ever since I first got my period I would always get it around the 21st of every month, that’s how it stayed for years..but now I have slowly made my way up to January 2nd now just from having my period a week early every month.. what does this mean is it normal or should I be concerned??