In 1930, the economy was going into a depression. Today, the economy is booming. It did help Saccone, although not enough to pull it off because he was a bad candidate, and his opponent was a good one, and this was an ancestrally Democratic area. But even then he nearly won. The economy will be even better by November if this keeps up.
I think the GOP will be fine in the midterms, and keep both chambers.
There's a political proverb that when the economy is bad, the economy is the issue. But when the economy is good, other issues take precedence. The GOP's problem is that other issues are bad for them.