How do i find out who is useing my facebook ?

[Rebecca]

[abraXus]

first off, unless someone else has your password, no one is using your facebook, you probably just think they are

if someone has your password, just change it, and make sure it's the not same password you use anywhere else on the internet - that will prevent it in the future

if there is actually someone else accessing your account (which is unlikely) there is no way to figure out who it is