Right now the Dems are ahead in five Senate races currently held by Republicans - that would give the dems - 49 Senate seats plus 2 independents that caucus with them so they would have control of the Senate:
1 - Hassan (D) over Ayotte (R) (Incumbent) 2 - Duckworth (D) over Kirk (R) (Incumbent) 3 - McGinty (D) over Toomey (R) (Incumbent) 4 - Bayh (D) over the open R candidate 5 - Feingold (D) over Johnson (R) (Incumbent)
Except for McGinty all the others have a comfortable lead. I suspect as Trump falls further behind other Senate seats will follow