This is a total based on the CNN website.  This total is obviously both unofficial and incomplete.  However, since I had some time today and since official returns aren't posted on SOS websites until mid December, I thought I would compile this.

CNN did not compile the votes of candidates who did not face a competitor.  In most states, these votes actually are compiled.  There were 34 candidates who were reelected without an opponent, 30 Democrats and 4 Republicans.  Obviously removing so many more Democrats than Republicans makes the national total closer than it would be otherwise.  That said, the aggregate vote total does suggest that the Republicans did close somewhat in the final days.

Total votes: 72,959,590 401 districts
Democrats: 37,384,882 51.2% 203 districts won
Republicans: 33,937,956 46.5% 198 districts won
Libertarians 600,715
Green 209,383
Others/Independents 826,654

Note: the 203 districts 'won' by the Democrats includes Texas 23 (22?) as the Democratic combined vote total exceeds the vote Republican Henry Bonilla received.

Recalculated numbers:
72,959,590/401 = approx 180,000 votes per district

If we assume in the 34 uncontested districts that 180,000 people also would have voted, and we assume that the winner would have received 130,000 votes and the loser 50,000 (I'm making these numbers up out of whole cloth, but we need some numbers)

we have an additional 4,100,000 votes for the Democrats and an additional 2,020,000 votes for the Republicans.

Total Votes: 79,079,590 435 districts
Democrats: 41,484,882 52.5% 233 districts
Republicans 35,957,956 45.5% 202 districts

Clearly, a 7% aggregate Congressional vote win was towards the lower end of the polls.

The following is the state by state totals (using only the numbers provided by CNN, not adding in my theoretical 'made up' numbers.)  There are about 10 other districts where the Republicans did not field a candidate and 6 other districts where the Democrats did not field a candidate.

Alabama 690,953 (3 uncontested districts (2D 1R))
Dem 224,350 32.5%
Rep 463,207 67.0%

Alaska 202,706
Dem 81,408 40.2%
Rep 115,062 56.8%

Arizona 1,132,596
Dem 481,258 42.5%
Rep 578,769 51.1%

Arkansas 750,101
Dem 449,568 59.9%
Rep 300,533 40.1%

California 6,541,706 (4 uncontested districts, 3D 1R)
Dem 3,695,593 56.5%
Rep 2,627,925 40.0%

Colorado 1,370,490
Dem 727,914 53.1%
Rep 571,699 41.7%

Connecticut 1,078,907
Dem 651,825 60.4%
Rep 420,995 39.0%

Delaware 254,213
Dem 98,350 38.7%
Rep 145,526 57.2%

Florida 3,727,239 (6 uncontested districts, all Dem)
Dem 1,496,686 40.2%
Rep 2,162,356 58.0%

Georgia 1,917,997 (1 uncontested district, Dem)
Dem 799,308 41.7%
Rep 1,118,689 58.3%

Hawaii 337,663
Dem 219,588 65.0%
Rep 118,075 35.0%

Idaho 443,800
Dem 176,757 39.8%
Rep 247,237 55.7%

Illinois 3,182,204 (1 uncontested district, Dem)
Dem 1,768,853 55.6%
Rep 1,399,427 44.0%

Indiana 1,645,452
Dem 802,751 48.8%
Rep 820,573 49.9%

Iowa 1,026,933
Dem 489,508 47.7%
Rep 519,796 50.6%

Kansas 826,117
Dem 360,356 43.6%
Rep 449,548 54.4%

Kentucky 1,244,535
Dem 596,402 47.9%
Rep 608,771 48.9%

Louisiana 900,642
Dem 294,100 32.7%
Rep 579,514 64.3%

Maine 529,679
Dem 345,296 65.2%
Rep 161,633 30.5%

Maryland 1,407,137 (1 uncontested district, Dem)
Dem 859,014 61.0%
Rep 503,595 35.8%

Massachusetts 1,067,292 (5 uncontested districts, Dem)
Dem 792,619 74.3%
Rep 197,722 18.5%

Michigan 3,516,993 (1 uncontested district, Dem)
Dem 1,793,200 51.0%
Rep 1,626,459 46.2%

Minnesota 2,178,617
Dem 1,153,624 53.0%
Rep 925,500 42.5%

Mississippi 582,527
Dem 251,415 43.2%
Rep 295,968 50.8%

Missouri 2,083,253
Dem 984,336 47.2%
Rep 1,043,683 50.1%

Montana 403,277
Dem 157,499 39.1%
Rep 238,031 59.0%

Nebraska 586,217
Dem 257,214 43.9%
Rep 329,003 56.1%

Nevada 572,533
Dem 286,761 50.1%
Rep 259,237 45.3%

New Hampshire 401,975
Dem 209,424 52.1%
Rep 188,774 47.0%

New Jersey 1,858,817 (2 uncontested districts, Dem)
Dem 948,740 51.0%
Rep 885,007 47.6%

New Mexico 550,639
Dem 306,865 55.7%
Rep 243,774 44.3%

New York 3,561,955 (4 uncontested districts, Dem)
Dem 2,285,296 64.2%
Rep 1,268,408 35.6%

North Carolina 1,842,726 (1 uncontested district, Dem)
Dem 935,490 50.8%
Rep 907,236 49.2%

North Dakota 216,485
Dem 142,121 65.6%
Rep 74,364 34.4%

Ohio 3,763,163
Dem 1,970,118 52.4%
Rep 1,784,993 47.4%

Oklahoma 905,048
Dem 372,822 41.2%
Rep 517,948 57.2%

Oregon 1,260,848
Dem 713,441 56.6%
Rep 522,846 41.5%

Pennsylvania 3,815,353 (1 uncontested district, Dem)
Dem 2,060,969 54.0%
Rep 1,705,435 44.7%

Rhode Island 372,030
Dem 264,101 71.0%
Rep 94,327 25.4%

South Carolina 1,072,364
Dem 466,473 43.5%
Rep 592,639 55.3%

South Dakota 333,576
Dem 230,473 69.1%
Rep 97,868 29.3%

Tennessee 1,712,426
Dem 860,025 50.2%
Rep 797,431 46.6%

Texas 3,995,661 (2 uncontested districts, 1D 1R)
Dem 1,783,791 44.6%
Rep 2,069,479 51.8%

Utah 548,161
Dem 234,024 42.7%
Rep 282,554 51.5%

Vermont 262,361
Dem 139,585 53.2%
Rep 117,221 44.7%

Virginia 2,148,308 (1 uncontested district, Dem)
Dem 810,365 37.7%
Rep 1,220,073 56.8%

Washington 1,644,074
Dem 1,003,287 61.0%
Rep 631,900 38.4%

West Virginia 446,333
Dem 258,438 57.9%
Rep 187,895 42.1%

Wisconsin 1,852,619 (1 uncontested district, Rep)
Dem 1,001,254 54.0%
Rep 836,054 45.1%

Wyoming 192,889
Dem 92,227 47.8%
Rep 93,197 48.3%

Although I haven't done it here, it's interesting to compare the state congressional totals with the Governor and Senate races.  I think, for instance, in Tennessee, though without knowing anything about the campaign run by Bob Corker, it's sadly difficult to conclude anything other than had the Democrats run a strong 'white' candidate, they would have won.