Mirena doesn't work for everyone.....not that any bastard bothered to tell me that
I had a 9 month-long period, before I begged the GP to take it out...stupid gynae couldn't see the problem with that though.
I've the endometrial ablation too.....lucky me. I used to have 14 day 'rusty knife in C-section scar' periods like you describe OP, with extreme flooding, but now have them just as bad, except with a break of 3-5 days in between so effectively like two a month. And now they are so irregular, I never know when the fuckers will strike :(
And, nice hot water bottle on the tummy no longer works....since my section scar wasn't stitched properly, neither was my resulting, incisional hernia, so I now have nerve damage too. How the hell can I feel period pain, but not hot or cold 
Can't take Tranexamic and Mefenamic acid either as they make me throw up....
Hormone injections were interesting....four years on and I'm still having the 'hot flushes' side effects.....
I really must go back and see what exciting treatments they have stored up for me to try next....I'm 34, can't have more children due to shitty hernia and ruined stomach, DH has had the snip anyway, but still the gyneacologist won't let me have a hysterectomy :(