Very Large Lump Found In Vagina

Past history of Polycystic syndrome with nil treatment. Had son 7yrs ago by C-section after many hours on inducing drugs as 3weeks overdue. Very irregular periods/weight problems all my life but particularly since childbirth. Just finished an extremely heavy and painful menstrual cycle yesterday. Very unusual symptoms in first 2 days of cycle - extreme back ache and cramping. Could not sleep without high doses of codeine (unusual for me as never use pain killers) Still having twinges and some deep seated cramping today. Sounds disgusting I'm sorry but thought I had better check if I had left a tampon in from previous period!! (usually use pads but did use a tampon last cycle) On internal exam I found a very large lump on the left wall of vagina quite high up. No pain when pressed but have had twinges in area since (not sure if this is paranoia) Can only feel half of lump which feels firm yet spongy and is approx 10cm. Have had extreme lack of energy past few months but put this down to unhappiness in general life. Have recently moved to knew town to start afresh. I have been single and celibate for past 9months. Any ideas? I am obviously very worried