Q: HELP ME FAST FAST FAST

Please turn off your caps lock.  All caps indicates shouting, is considered rude and is difficult to read.  Many will not read such posts.

Your music is gone from where?  Your computer?  Your iphone?

Why can't you sync?

RIght account?

Please explain your issue.  Your post is not clear about your problem

Woahh.. Slow down. Do you mean on your iphone or your computer ?

If its your phone, then plug it into your computer and sync again.

Can you please explain exactly what happened and on what device ?

If you have Updated iTunes on your computer...

Try here  >  http://support.apple.com/kb/TS1967

From here  >  http://www.apple.com/support/itunes/install/