The site that makes the basic Nitrogen for fertiliser has closed, temporarily, because the price of the gas it uses in production has risen too high recently.
If the price of gas levels out, it will restart production... if not, who knows what will happen
Manure (from animals or sewage sludge) is a good replacement, so yes, farmers will be looking at the alternatives. This is why some farmers have stressed the need to return to mixed (animal & crops) as the natural way forward - although some see it as a backward step - but it is a maintainable system.
If you can afford to, I suppose it is worth buying enough of your preferred brand for next year - and hope things sort themselves out soon.
I don't need any more as I recently managed to buy 2 bags of Orgrow, on offer at very reasonable price.