54MB is actually very fast, but it always loads 500kB and then suddenly back to 0B for a minute or so. That makes no sense and ensures that a 50MB download takes an hour
Otherwise, when your internet goes, either the servers are overloaded or there are thousands of small files that are being changed.
This happens in both cases. It only helps to wait or try it later.
Pull the udder out of the plug and put it back in again, I had the same problem 3 days ago.