What Causes Excessive Menstrual Bleeding And Spotting In Between Period?

I am 34yrs old, 6ft, 115kg, a smoker and mother of 3 children. I have always had heavy periods but not as long or as frequent as now. Generally I am well and fit. For the past 6 months I have had excessive menstraul bleeding (bleeding from 6 - 14 days) every 10 - 24 days. My ferritin level is 11ug/L. I have been experienceing spotting/ bleeding after sex as well as a dull ache in my pelvis (above my pubic bone) during and after sex, aswell as spotting between periods also.I have also been having labour pain type lower back ache which is affecting work. My Dr found a lesion on my cervix a few days ago during my PAP. I had 2 incidents of genital warts in my late teens and early 20's. This week I have had 2 episode of dizziness/ room spinning? I'm a nurse and I'm starting to worry a bit, could you help?