01/03/2006 at 04:00 PM EST
Lindsay Lohan was admitted to a Miami hospital Monday night after suffering a severe asthma attack and is now "resting comfortably," a source close to the actress tells PEOPLE.
The Mean Girls star celebrated New Year's Eve in Miami, hosting a party at Prive Nightclub.
Lohan, 19, is set to begin shooting her new film, Chapter 27, in two weeks. The movie, about John Lennon's killer Mark David Chapman, stars Lohan as a Lennon fan who befriends Chapman (played by Lohan's once-rumored beau, Jared Leto) just days before he assassinates the musician in New York.