I think this scenario is somewhat likely and credible given the dynamics of the race, but while on the site, I found the following projections for U.S. House and Senate:
House:
Current D: 193
Projected D: 191 (-2)
Current R: 242
Projected R: 244 (+2)
Did the Republicans manage to gerrymander the entire country this badly, or is this biased projection? I knew we would have difficulties reclaiming the House this go around, but how can we lose seats in this climate?
You're forgetting that reapportionment between the States also favored the GOP. Of the twelve seats that were switched between States, 11 were gained by GOP states and only 1 from Democratic states. 7 were lost by Democratic states, 3 by swing states and 2 from GOP states. So even before considering intrastate gerrymanders from redistricting, the GOP gained 7 or 8 seats just from reapportionment.
(Double checked my math and saw that the GOP actually gained more than I had thought at first.)