I'm going through the same thing atm,
I'm currently on day 48 of my period, started really light on 14th January, carried on light for a week or so then spotting for a few day then heavy, spotting again and so on , now I'm going through 3rd heavy day, heaviest since 14th Jan, back ache horrendous agony just peeling potatoes or washing dishes, not sure how much longer it will go on , last time it was this long was last April and lasted 46 days only had 5 periods last year total,
Jan 30th to Feb 20th 22 days
March 28th to Apr 3rd 7 days
Apr 14th to May 29th 46 days
July 6th to July 26th 21 days
Sep 26th to Oct 17th 22 days
And now this one
Jan 14th ..................... till whenever
As you can see literally all over the place and the year before last was no better,
Really hoping that it won't go on much longer.