Mirena can last UP TO 5 years - so there is a chance it is no longer quite as effective - but that would manifest itself in spotting or return of periods - the mirena has no effect on the endo that remains in the body - but the benefit is that if you have had surgery to remove endo - then stop your periods , that stops the development of fresh endo from any backflow of menstrual blood along the fallopian tubes ...that's the bit where the mirena is great for endo. But if you had left over unattacked endo - it will still remain active while you have a mirena installed.
I have endo in bladder and bowel which is still active - but I don't have menstrual periods becuase the mirena (covered in goop) is trapping the lining of the womb in place and stopping it from detaching and slewing away each month. It certainly helps my quality of life hugely not to have the pain and miserable mess of periods, but there is definitely no discernable impact on the residual endo that I know I have been left with after my last op. it still remains active once a month.
If you were left with any endo lesions after your last surgery it could still be developing each cycle and bleeding and spreading even though you are not actually having periods from the uterus. so yes it could be that the endo that remained has started to cause more side effects for you.
Have you kept a food diary to try and figure out which foods or drinks are making this bloating issue worse? Worth a try and possibly adopting the endo diet measures to try and avoid the foods that can make things a lot more uncomfy, and stick to what you find to be safe foods for you.
Endo and adhesions can compromised the digestive systems ability to work properly - and any foods that trigger gasses or promote build up of bloat fluids can cause those to be extra hard to get rid of - and cause more pain in you than they would necessarily cause a person with a healthy digestive system.
Bloat is one way our body provides a cushion of protection from hurt (much like adhesions are) - it works just like blisters on the skin do.
It's a natural reaction by parts of the body that have been irritated
Something you're are eating is irritating and causing this reaction inside, which feels all the worse because you have a compromised immune system, anyway with having endo, and the damaged caused by endo, adhesions, surgeries and so on can restrict the usual flow of body waste through your digestive tract and any irritants get stuck there for longer making things worse.
So I would definitely recommend you keep a careful eye on what foods you have eaten that trigger the worst of these post meal pains and try and cut out those triggers from your diet. There are bland foods that don't tend to be a problem - and limit what you eat to the friendly foods. I am not religiously sticking to the endo diet - but If i accidentally take any of the foods I know cause me problems its not very long before I am regretting what i have eaten or drunk.
Much as I luve diet coke - it doesn't at all like me. so that's on my banned list, also anything with alcohol even small amounts in a trifle - I have to avoid.
I am rather partial to sprouts but they cause gas - and trapped gas pains are whoa so painful and the gas being stuck on the way tends to trigger a fluid bloat build up too.
So I try - for the most part- to avoid those food I know I will regret having scoffed even though I love some of them and it really annoys me that i can't risk the aftermath. If I have the next day off - ie the weekend then I do sometimes treat myself to foods on my banned list - knowing that I have enough time to calm things down before having to go to work on Monday - but I don't do that too often. it hurts too much.
If you are not yet spotting every month and the spotting is getting increasingly heavier then the mirena is still hard at work and doesn't need swapping..yet.