No, because there's this thing called 2016, when all of those Tea Party Senators come up for re-election. There's a good chance that Democrats gain as many seats two years from now as Republicans could gain this year.
Now, I'd panic/care if there was a possibility that we could maintain the number of seats in this election that we currently have, because 2016 would then produce the possibility for a filibuster-proof majority, but alas...
Whether Democrats have a majority or not come 2015 in the Senate won't affect legislation or policies that are passed over the next two years, and won't stop Democrats from regaining the Senate come 2017.
Maybe, but I wouldn't be so quick to assume 2016 will be a big Dem year. 2012 was supposed to see GOP gains and look how that turned out.