The red-blue thing was not fixed until 2000 (although it's still not a "rule," just a convention that the media has adopted), but it was not necessarily the opposite. It varied from year to year and news source to news source. One year CNN did red for Democrats and blue for Republicans and ABC did the opposite, making it very confusing when you switched channels.
Obamacare's not going anywhere. For one thing, they don't have the votes to override a veto, as already mentioned. And for another, it's working too well for too many people. Plenty of moderate Republican senators (think Susan Collins from Maine, for example) do not want to see it repealed. But the diehards will undoubtedly put it up for a vote, and even some of the ones who don't actually want to see it repealed will go along knowing full well that it will be vetoed. This is 21st century America — government by filibuster and veto.
Last night was a little bit worse than expected. The House and Senate did more or less what was expected (at this writing the Louisiana senate race will have to go to a runoff and Alaska and Virginia still haven't been called, although my guess is that they will both go red), but the governorships were a disappointment. I was hoping to see Sam Brownback ousted. Oh well.
This was a very Republican year for a couple of reasons. For one, most of the Senate seats up were in red states, so the Democrats started off with a disadvantage. Then you have to factor in the mid-term effect, usually more pronounced in second presidential terms, in which the party in the White House almost always loses seats. And finally, you have an unpopular Democratic incumbent. Considering the fundamentals, there is an argument to be made that the Democrats should take heart. The only people who vote in mid-terms are cranky old white people, not exactly their base. It could have been worse (for example, Scott Brown could have won in NH, which would have made him so insufferably smug that his head might have exploded; now at least we don't have to hear about his daughter's singing career any more). Two years of these guys in power, and more gridlock, will only work in the Democrats' favor in '16.
And so the cycle continues.
Expect a lot of vetoes over the next two years. You might also see a conservative Supreme Court justice or two step down, now that the odds of getting an ideologically left-leaning justice through the nomination process are exactly zero (which is ironic since Obama doesn't appoint particularly liberal judges anyway; in a lot of ways he's a very conservative guy).