Hello, stranger!!
It's really hard to say. One one hand it's not unusual for the 'other' party (in this case the GOP) to gain a majority in either/both the House and Senate during the midterms when the previous general election has resulted in a POTUS of the same party as the current majorities in the House and/or Senate. At one time this was part of the 'balance of power' and the three 'powers' (POTUS, House, Senate) worked together for compromise in order achieve their aims. But now it's absolutely 'party politics' above all and all about blocking the 'other party' no matter what they're trying to do. If the Dems found a cure for cancer, the GOP would block it, just because it's the Dems agenda. I can't put my finger on when this started. I remember some of it during the Clinton administration, but McConnell said it 'loud and proud' during the midterms in 2010, during the Obama years. That they would block every piece of his legislation so he'd be a 'one term POTUS'. Didn't work, though.
On the other hand we've never had a POTUS like Doofus so you just don't know how the more moderate voters will vote. Plus it seems as if a lot of the more conservative voters are flat out lying about who they'll vote for. Some avowing Doofus' chosen candidates to 'keep in' with him, but secretly planning to vote for other candidates. Others denying Doofus due to 'public opinion', but secretly planning to vote his chosen candidates. So once again, the polls are useless
You'd think that the fear of the hardcore right wing with their anti-everybody-who-is-not-a-white-male agenda would be enough to bring out Dem & liberal independent voters in droves as well as any number of moderate (ie sane) GOP and independents, especially in purple states. But I'm not sure it will.
I live in a safe Blue state as far as the Senate goes. But we're now in a brand new congressional district and the House seat is truly up for grabs. The candidates are a moderate Dem vs a hardcore Trumpinista. Frankly, I'm scared shitless.