The advice so far is very sound; I will add this as well. In the future, work with a contract, and never work without one again. This first thing to do in future projects is define the scope and make sure that both you and the client are in agreeance on what will be delivered and when for how much.

For this project, the blame is entirely on yourself. That is not meant to be harsh. No contract, you were not clear on what you were doing but took the job and did not set expectations correctly. This is a learning experience - communicate where you are with the project to the client on a regular basis from now on.