What could be going on!

Spotted 16th & 17th (light pink / brownish).

Nothing on the 18th.

Expected Period 19th and it didnt come.

Negative pregnancy tests on the 25th & 30th.

Since missed period I have had lite cramping and breast discomfort, lack of energy.

Now 20 days after my missed period, (TODAY) there is extreme cramping and discomfort and lite bleeding so far.

Typically my periods are consistent and come somewhat regularly. Not very much change in stress, eating habits, physical activity etc.