Not to belabor the point, but no, it's not what happens after every election, at least in Germany. Germany tends strongly towards a two-party coaliton in the past and that's no longer a given at all.
But regardless, I think it's significant to note that the increased turnout didn't benefit Merkel, the CDU/CSU, or the SPD at all. The FDP got back into Parliament and the AfD jumped in hard for the first time, all of this at the expense of the CDU/CSU and the SPD. Not exactly what was expected, no?
And the SPD has good reason, I think, to switch to opposition. Sure, it could be negotiation, but its leadership has to look at their losses--40 seats--and allow that maybe the party membership is unhappy. Joining hands with Merkel may not be the right choice for the party.
The AfD has estimated that about a third of its support comes from Russian-speaking voters, several million of whom have settled in Germany since the 1980s; they now make up as much as 5% of the population. On Sunday night, one of the leaders of the AfD, a vocally anti-immigrant and nationalist party, appeared to concede – somewhat paradoxically – that its core constituents are themselves immigrants.