same thing happened to me, it's a coil pack, or possibly 2, when the sparks are not firing correctly the balance of the crank goes all over the place.
don't drive it, it's not good for the internals and it certainly isn't any good for the catalytic converter (or however you spell it)
some recovery people will actually go and buy the coil packs and change them for you if they can find a shop open, they are about £40 each from audi, i managed to source some from a scrapped 2007 a6 on ebay, all 4 for £80, do some revision on the part numbers, the new part numbers are more reliable.
to change them yourself will take about an 40 minutes if you take the sparks off too to give them a clean as they will most likely have fuel all over them
don;t just change 1 or 2, change them all