You need proof of identity and proof of citizenship. Drivers License will work for proof of identity. For proof of citizenship, you need your birth certificate or baptism certificate. If you go with a drivers license only, you MAY pass but more likely they will throw you into Immigration Control and you will stand in line for a LONG time to be asked a million questions then they will let you in.
Been there, done that. Find your birth certificate, it makes it much easier.