I remain baffled as to why, in an age of railroads and telegraphs, that it took Congress three months to get back to Washington and respond to the state of war. Seems like an urgent situation to me.
The Senate met from March 4, 1861 to March 28, 1861. That session had been called by President Buchanan. Lincoln called for the extraordinary session which met beginning July 4, 1861 (by tradition it would have begun December 1, 1861.
Perhaps we are applying presentism in thinking there should have been greater urgency. Perhaps both Houses recognized that the resolution of the situation was the responsibility of the Executive. Certainly, when one reads the Congressional Globe entries, it appears members proceeded in a calm, unhurried, deliberative fashion: the Senate confirmed Lincoln's call for volunteers and authorized military spending.