On the family planning injection depo no periods for 6 months now i ha e terrible menstrual pain but no periods and back pain?

Menstrual type pain "with no periods for six months" may be caused by fluctuations in estrogen production, with concurrent endometriosis. "Depo" injections can inhibit ovulation and since it is a form of progesterone, true "periods" are often irregular to absent. Ask about low dose oral bcp's, which stop all ovarian hormone production, and should stop the painful cramps.