TRAIN-wreck pop tart Britney Spears continued her club-hopping tour of Manhattan Tuesday night when she indulged in a frenzy of drinking, dancing and making out.

Confirming rumors that she and Isaac Cohen are no longer an item (OK! Magazine reports Cohen dumped her over the phone), spies said Britney was "partying like a college girl looking to get laid."

At 8 p.m., just as Zitomer was closing, Britney entered the Madison Avenue department store near the Carlyle Hotel and bought several items, including a red fur head wrap and a pink rabbit jacket.

After she was a no-show at the chaotic Heatherette show (supposedly because she was "really scared" by the press), Spears and friends had dinner at touristy Rue 57. She next headed to Marquee, where sources said she was dancing with her girlfriends and "demanded all alcohol be kept far away from her."

But other witnesses weren't buying that. "She must have been drinking secretly in the bathroom," said one. "Because she was falling all over the place. She was also chomping on lollipops from the bathroom all night. And she didn't leave any money for the bathroom attendant."

Spears' wild night continued at club Tenjune, where she was seen arriving at 2:30 a.m. with a group of friends. "Britney was completely hammered," said a witness.

Again, the tank top-clad party girl asked that no alcohol be put on the table - but clubgoers saw her dancing on the banquettes and "drinking what looked like vodka and O.J."

A source told Page Six that one of the people who followed her from Marquee to Tenjune (described as "a scruffy-looking guy") was "hitting on her all night, but she wouldn't even look at him.

"Then a model guy came to her table and she started making out with him." Spears ended her night with a visit to McDonald's.

Reps for Tenjune said, "Britney was here, but she was not drinking." A rep for Spears told us, "Britney was at Marquee with friends." Marquee had no comment.