Russians retaliatory sanctions on the EU, although may harm the Russian economy will not sink it. Russia's economy is stronger than many EU states and the less the EU export and the higher the energy prices of the energy imported by the EU the greater it would have a direct negative impact on any purported crawling EU economic recovery. When people point out Russia's economy will this and that they forget the state of our own economies and under-estimate the harm our own governments actions will have on us all, by forcing Russia into a retaliatory position.
The global economy is in no fine shape to be messed around with, unfortunately that's what the E.U, U.S and Russia in retaliation are now doing, messing with the global economy and threatening economic recovery across the board.