Cheryl Cole is said to be a nervous wreck since leaving Derek Hough behind in LA and sources say that Simon Cowell is not being the most sympathetic pal.

Cheryl left Derek when she returned to the UK earlier this week, so that she could record the judges houses stage of The X Factor. Newspapers had reported that the ’3 Words’ singer dumped her dancing boyfriend before leaving America, but pals deny this and say that if anything, Cheryl is more dependent on Derek than ever before.

A pal told Now magazine:

“Cheryl’s in a real panic. She’s been joined at the hip to Derek since shortly after she split from Ashley.”

“Now she’s worried what she’ll do without her ‘rock’. She’s been having panic attacks at the thought of them being apart for so long.”

They added: “Derek was there for her when she had malaria and also when she was struggling to come to terms with the divorce. They have a real bond.”

However, Simon Cowell has issued a warning to Cheryl, telling her to ‘pull herself together’ and prepare for the ITV show.

The source continued:

“Simon asked her if she’s ready to come back. She assured him she was, but was petrified about it.”

“As nicely as he could, he told her she was being silly and that he wants the old feisty Cheryl back sooner rather than later.”

They claimed: “Simon can see Derek has been good for her, but he thinks she relies on him as a crutch too much.”