Britain’s The Sun is reporting that Britney right before her performance went into a rage over her hairdo (and I can see why!) and was so upset she had to be given anti-depressants by her doctor.

An MTV source told The Sun:

“The scene in the dressing room before the show was one of absolute blind panic. She knew she hadn’t rehearsed enough and was going to mess up the whole show and possibly her career – then she saw her hairdo and it was the final straw. She went into a wild rage and started lashing out at everyone — including her stylist.” In a desperate attempt to quick resolve the pre-show problem, Brit’s handlers at the Las Vegas Palms Casino fetched her doctor, who had the embattled songstress pop the prescription pills.

The source said: “Britney took enough to floor an elephant. They calmed her down — but were clearly too effective.”

In other Britney Spears news, she and Kevin Federline agreed to meet face to face yesterday in a lawyers office.

A source tells me Spears and Federline may be meeting—right now!—at the Los Angeles offices of Spears’ attorney, Laura Wasser.Federline is seeking primary custody of their two kids, Sean Preston and Jayden James.

Buzz around the building has it that the two arrived separately about an hour ago. Federline was spotted entering through the main lobby, while Spears apparently took a more private path through a side entrance.

I’m told they agreed to meet in an attempt to avoid attending a court hearing scheduled for this coming Monday.

In the mist of the custody battle, the press (Us Weekly) continues to try to draw blood from Brit-Brit for her MTV VMAs.

Britney Spears didn’t end up working with Criss Angel on her VMA comeback performance, but her stage show was certainly full of illusions. Her lip-syncing was meant to give her the appearance of an actual singer, and her spray-on tan was supposed to make it look like she’d spent hours in the gym (as opposed to the bar).

“She had an ab-defining spray tan pre-show to create the illusion of more tone,” a source tells Us.