I started a progesterone only pill 3 weeks ago to see if some abnormal cramping I had was due to endo. I think it's helped but I just had some (red) spotting. The pack I have doesn't have any placebos so I don't have to get a period. I missed one pill & take the pill within the same 1-2 hour window everyday. I've had some slight cramping & breast tenderness but I did last month too. Why would the bleeding occur?