“I’m staying in this race until there is a nominee, and obviously I’m going to work as hard as I can to become that nominee,” Mrs. Clinton said after an event in Shepherdstown, W.Va.

As adamant as Mrs. Clinton appeared on Wednesday, several advisers said that how long she would stay in the race was an open question. Some top Clinton fund-raisers said that the campaign was all but over and suggested that she was simply buying time on Wednesday to determine if she could raise enough money and still win over superdelegates, the elected officials and party leaders who could essentially hand Mr. Obama the nomination.

Highlighting the financial woes of Mrs. Clinton’s expensive battle against Mr. Obama, campaign officials disclosed that the $6 million in loans she made to her campaign had come in three installments since April 11, with the last two since May 1. Mrs. Clinton and her husband made a separate $5 million loan to the campaign after the Feb. 5 contests.

Mrs. Clinton is willing to put even more money into her campaign, said Terry McAuliffe, her campaign chairman. “Senator Clinton has anted up and is fighting on,” Mr. McAuliffe said. Other advisers said in interviews that her campaign was nearly out of cash, raising questions about what kind of campaign she can continue to run. The campaign said, however, that it was running advertisements in West Virginia and in Oregon, which has its primary on May 20.

Clinton advisers said they were concerned that the candidate’s online fund-raising, which boomed after her victory in the Ohio primary in March and in Pennsylvania in April, had slowed by comparison on Tuesday night and Wednesday, and that her donor base was either tightening somewhat or playing wait-and-see, despite her public appeal for money on Tuesday night. Clinton aides did not send out the near-hourly e-mail blasts bragging about online donations that came after previous successes.