I've just been told that PPS is taxable - does that mean I was supposed to take tax out on the PPS payments I received last year?

Will I have a debt now? It said I recived about $11k and total tax withheld $0. I know you can earn $6K tax free so does that mean I now have to pay tax on $5K??

Should I be taking a certain % out every fortnight from now on??

Help and TIA!!