Is your husband as affected by the noise?
I'm wondering if your fibromyalgia could be making it worse - noise intolerance isn't an uncommon symptom, and constant or almost-constant noises are supposed to be the worst triggers. Then as your fibro flares as a result of the noise, the noise becomes more intolerable. The only real solution is to move away from the noise though - it's unlikely, if this is what it is, that the restaurant would ever be suitable to live next to. I have a friend who fibro that used to live near a train track with one train an hour between 9am and 9pm - no freight trains or anything - but during one bad flare she developed noise intolerance and she couldn't live there after that, every time the noise went past it set her off. They had to sell the house
She did make a good recovery when she moved somewhere very quiet, though.
The only way that I can think of to test that is to ask your husband or a good friend who visited often if they think that the noise is louder, and ask them for an honest answer? You still might not get one, because it's quite a leading question, but hopefully you'd get an idea of whether the increase should be enough to make it as bad as it is for you. It's possible that them extending the hours and running it over night combined with your flare at the moment has caused an intolerance.
If it's not the case, Environmental Health will come to record the sound - they left four recording boxes at different points in our flat when they came to us a few years ago, and collected them three days later. It took them four weeks to analyse the data, and then they wrote to the landlord of the building and let them know that the noise level was too loud. The landlord did nothing so got a few letters, over about two months, and a few fines, and then Environmental Health got us released from our rental contract so we could move. They intended to take the landlord to court over the noise pollution but as it's a low-priority case, they didn't expect it to be quick.
If it is a health thing, you might find that spending some nights away helps, if you've got somewhere quiet that you could stay. Although I expect, with fibro being the git that it is, it would return as soon as you were home.
To be honest, it may be that your only solution is to move whether they are being too loud or not - in my experience, the council is relatively toothless and they'll probably get a lot of warnings, then fines, before court action is even suggested, and then that can take a while. And if it's within allowable ranges, your intolerance is only likely to get worse the more you are exposed to it.