I Have Had Severe Back Pain/coccyx For Over A Year. Could It Be Cancer ?

Hiya, i am 42yr old women with 2 children (12 9) i have had severe back pain/ coccyx for over a year, problems with heavy periods and continual bleeding, a lump/ bulge in my lower right abdomen , frequent weeing and keep getting constipated and have lost over 4 stone. Had scan done 8 months ago which showed large fibroid and gallstones. Had endometrial ablation done 4 months ago which successfully stopped bleeding. Had incredible pain afterwards. and dr didnt find a large fibroid? Other symptoms still continuing and worsening. Had cortizone injection in coccyx recently, gave some temporary relief. Just had mri done, showed large ovarian cyst , is this the lump i can feel? Is it the cause of my symptoms? was the cyst originally misdiagnosed as a fibroid? What happens next? should i be concerned, could it be cancer ? or would that have shown on mri ? please help, still in lots of pain and scared too. Thankyou.