What’s going to make the difference is whether we are as motivated as the Democrats. The Democrats are very motivated. The Republicans (both the rank and file, the GOPe, and the President) are not doing much to motivate the GOP voters. Instead of attacking each other, they should be attacking the Democrats.
There have been a few races that the GOP lost recently because the Dems were anxious to demonstrate how motivated they are. The GOP needs to get itself motivated, or else Nancy Pelosi will soon be Speaker again, and will be leading an impeachment campaign against Trump.
One issue that could motivate Reps (and Indies) is illegal immigration.
The Dems knew if they continued to keep the government shut down the Republicans would pound them by saying they favor Illegal Immigrants over the Military & Seniors & Citizens, etc. and they would be annihilated in the mid-terms.
Unfortunately instead of getting everyone mad the Dems, Trump and the Republicans came up with their own Amnesty plan and this new spending bill does nothing on the Wall and illegal immigration.