"As a striker playing for Liverpool you are always going to have critics if you don't score, but they are right as I'm not playing my best footballer at the moment," he told liverpoolfc.tv.
"Sometimes in football you are really lucky and everything you touch goes into the net, but sometimes you are unlucky and you get some bad moments, but I'm working hard to get back to where I belong."
The player also insists he hasn't lost his confidence in front of goal and said the backing from manager Rafael Benitez gives him a real boost.
"The manager has always had confidence in me and he always protects me," he added. "I remember I got criticism when I had some chances against Blackburn and he was one of the first people along with Stevie G who defended me and kept my confidence up."