Could Missing Periods And Back Pain Be Side Effects Of Regesterone?

i am 41 years old and i do sex 8-10 times in a month. I had my last menstruation in August 25 and then nothing in september. i don't want to be pregnant. i checked through the kit and it states negative. i had regesterone also on regular basis but nothing yet. i am having severe back hip pain. what shall i do now? is it due to regular consumption of regesterone. Kindly reply