Vermaelen said that he is not sure why Arsenal have experienced a sudden slump in form.
He told Sky Sports News: "I am very disappointed but it is difficult to explain why so short after the game.
"We wanted to put things right but it was the same story. I think everybody gave 100% but we are finding it difficult at the moment because we don't create enough chances to score goals.
"These moments are difficult but we still have to work hard and if we do that every day I think we will be OK."
Arsenal entertain Queens Park Rangers on Saturday looking to avoid three defeats in a single week.