What Causes Frequent And Heavy Menstruation?

I am 40 yrs old and an identical twin a couple of years ago my twin had to have a full hysterectomy because she had cancerous cells in her cervix...and since November I have been having more and more periods a month...and I have always had just one period a month my first when I was 11 yrs old...in December 2014 I had 4 periods the last starting on Dec. 20th and ending Dec.25th and then I started bleeding really bad yesterday and have had to change twice today already from bleeding through my pad onto my clothes and I have never bleed this bad I made an appt with my twin's OBGYN...my question is could this be the start of menopause or something more serious?