What Causes Prolonged Periods With Excessive Weight Gain,dizziness And Headaches?

Hi I am 47 years old, I have been on a non-stop period for over 8 months,extreme weight gain over the last yr,almost 80 lbs. Sometimes going though 2 boxes of tampons a day. Tired, dizzy,sharp pains can't sleep,skin changing,headaches. At this point getting kind of scared. Feeling like a prisoner in my own home, Scared to leave never knowing when the bleeding going to hit hard.I have always been active but now no matter what I do I can not even lose a pound. I have an appt to go see Dr. on July 11 but I was just trying to get some answers here.