Lower back pain after crossing the dates

There are number of reasons why your period might be late. In fact, every woman experienced late period at least once in life. Pretty much anything, from strong emotional events (like break-up), stress, some infection like throat infection to female hormones related unbalances could cause your period to be late. You can do the pregnancy test again, to ease your mind, but you have to take into account the well profen fact that the more you worry about your period, the more stress you put on yourself, so the period is even later.