Democrats squeak by a majority in the House, loose seats in the Senate.
Really now it’s a mixed bag, if republicans kept a majority in house and senate there would have been likely violence in the streets. So it’s basically going to be stagnation and gridlock in congress before it reaches the President's Desk.
Basically the only thing that will get done is judge appointments and Executive Orders. Which Executive Orders are the weakest act the Federal Government can produce as the next President can just sign those away without going through congress.
It was hardly a historic win for Democrats though as these results are hardly damaging to Republican President Trump, based on historical trends this election points to a 2020 win for Trump as he is preforming in his first primary like most presidents who won their second term. But historical trends are not the election in 2020, just don't trust any media calling this a "huge loss" for Trump
What does that mean for preppers though?
Biggest threat is long term Government shutdowns, infrastructure issues, and currency value loss.
Moderate prep will get most though any of these issues if they crop up.
If you have a government job or have a job that has government contracts, or if you depend of Government assistance programs be sure to prepare for shutdowns and money loss, have some funds set aside for this as well as food stocks.
I wouldn't expect a gun grab or any oppressive anti-prep legislation get though, let along any true legislation to get though congress in the next 2 years.