Heavy bleeding for two weeks at this age warrants an immediate attention by a Gynecologist. A perimenopausal bleed needs a through per vagina check up along with Ultrasound
of abdomen and if required a D&C procedure.
I could think of a number of conditions with this symptomatology however I wish not to threaten you at this hour. A symptomatic treatment for back pain
is not going to end this.
Hope this address the urgency.