The Championship strugglers beat the seven-times FA Cup winners 2-1 after extra time in their third-round replay after Liverpool had been less than a minute away from securing a fourth-round tie against Premier League rivals Burnley.
Liverpool are 12 points behind Chelsea in the title race and have been knocked out of the Champions League, League Cup and now FA Cup, with little left to play for this season apart from the Europa League.
"At the end, we are not in the competition any more so we have to think about the future," said Spaniard Benitez who has been in charge at Anfield since June 2004.
Benitez was asked on ITV if he thought his team were good enough.
"It depends on your point of view, but there were too many things I did not like," he said.
CRITICISM COMING
Benitez hinted at his displeasure with the referee.
"Sometimes we are playing better, sometimes we can improve," he said without being specific about areas of the team.
Asked if Liverpool's poor performance underlined their dependence on Steven Gerrard and Fernando Torres who both went off injured, Benitez said: "Not really, we can score goals without them on the pitch.
"They are very important for us but there are other players who can do a good job too.
"If the critics are fair it is OK. If it is not you cannot agree with them.
"If they decide they have to criticise, well it has been like that for three months."
Former Liverpool defender Mark Lawrenson told the BBC: "It cannot go on for much longer. There just hasn't been any improvement in performances - if we say average, we're being kind.
"I'd probably need an hour to discuss what went wrong tonight for Liverpool. Five or six of that team tonight simply aren't good enough. There will be calls for Rafa Benitez to leave."
While Benitez was struggling to find the answers to his teams problems, Reading's caretaker manager Brian McDermott was delighted.
"I thought our guys were terrific. It was a really, really good performance. We were unfortunate to go in at halftime 1-0 down because we had three or four chances that just went wide, but you have to think you're gonna get another one.
"We were good value tonight - the lads were all brilliant."
