Hello,
You are on pills past 20 plus years. You only have periods on the sugar pill week. Presently, you are not on the sugar pill week and have started to bleed. You also had a severe lower
back pain. Temporary dips in progesterone-
estrogen levels before the next tablet is taken may cause bleeding as the womb lining thickens. Similarly sudden drop in the estrogen level which stimulates the womb lining to shed, causing a withdrawal bleed, in case the pill is taken late or missed.
If by mistake two pills are taken excess estrogen may stimulates the womb to have a thicker lining and bleeding may occur. Certain medical conditions like cervical polyps,
fibroid or
endometriosis can also cause irregular bleeding. Cervical and endometrial cancers can also present with irregular bleeding. Chlamydia and sexually transmitted infections may also cause irregular bleeding. You are suggested to get clinically examined by a gynecologist to detect the factor that caused bleeding. Get
STD tests done to stay on the safer side.
Take care. Hope I have answered your question. Let me know if I can assist you further.
Regards,
Dr. Nupur K., General & Family Physician