Need Help On A Movie!

I remember seeing this on USA UP ALL NIGHT but I cannot remember the name of the movie.

It starts out with someone narrating the movie about how they went to a party on the beach. It turns out that it is some sort of vampire movie that takes place. All of the people who are friends are trying to get rid of the vampires. Two of the women fall victim and get captured and are chained up. By the time the they go to save their two female friends they have been bitten and turned into a vampire as well. At the end of the movie you see the two women chained or tied down to the bed kicking and moving around. The doctors and all cannot figure out what is wrong with them.

Can anyone tell me what this movie is called? I would appreciate that a lot! Thanks!