Jen, I think you are the poster who gave me my Christmas NN - a very belated thank you! And I'm very sorry to hear about your periods. FWIW I had a coil (though not a Mirena) and it gave me the worst periods I have ever had in my life - worse than they are now. But to each their own.
I don't think I have a right to complain, actually - I usually have 2-3 days of grumbles in the runup - the worst of that is the splitting headache which nothing will touch. This is the only time I ever get headaches, it's definitely hormonal.
Then when it all kicks off, I will usually have one really, really, really bad day where I need to change my sanitary arrangements every 2 hours or make a mess. This comes with cramps that no painkillers will touch either.
However, once that day is over, I'm usually OK. Very rarely I'll have one where the pain lasts 2 days.
Yours sound much, much worse than that. Are yours getting heavier too? Mine so are, I made a mess of the bed last night despite triple protection and a midnight change
.