The top chart is from a Gallup Poll -- done between November 9th and 13th of a random national sample of 1,019 adults, with a margin of error of 4 points.
The bottom chart is from an Economist / YouGov Poll -- done between November 12th and 15th of a random national sample of 1,659 adults, with a 2.8 point margin of error.
The charts show that the Democratic Party is still viewed more favorably than the Republican Party, and the public blames the Republican Party more for the dysfunction of the current Congress. If these are true, and I believe they are, then why did the public keep the Republicans in charge of both houses of Congress? There are two reasons.
The first, and most obvious, is the effective gerrymandering the Republicans were able to do in many states back in 2010. It matters how congressional districts are drawn, and in 2010, the Republicans drew some heavily-Democratic districts and a lot of districts that favored Republicans by smaller margins. It was unfair, but politics often is. The Democrats need to do a better job of fighting this gerrymandering in 2020 (when the districts will be redrawn).
But their was another reason for the GOP keeping control of both houses in the 2016 election -- straight-ticket voting. Note that House Republicans got 52% of the vote in this election, compared to 48% in 2012. And in the senate races, the Democrats won every race in states carried by Clinton, while the Republicans won every race in states carried by Trump. That shows there was a lot of straight-ticket voting in this election -- probably more than in other recent elections.
I still believe Hillary Clinton is a good person, a good politician, and would have made a very good president -- but she was damaged by over a quarter of a century of incessant lying by the right-wing (and in the primary by the left-wing) more than most Democrats (including me) realized. She simply didn't have the long coattails need by a presidential candidate to bring the straight-ticket voters to the Democratic Party (and help down-ballot candidates).