Still in pain even while on depo

[-grumpy]

Hi, I am 32 years old and was diagnosed last year with endo in pouch of douglas. My gynae advised it was quite extensive after i underwent a lap in Aug 2013. I've since been on the depo but only recently started experiencing severe pain in my lower back,vagina, left side and sometimes weakness in both my legs. I also suffer from bloating. I have trouble pooping, too painful). the strange thing is I'm not even bleeding. Why am I still in pain?