It's always horrible when you don't get the results you were hoping for.

To clarify, do you meaning failing as in less than 50%, or under the 70% threshold for medicine? One will affect the papers you're allowed to take in sem 2.
To be applying for graduate entry, you will need to complete an undergraduate degree in the minimum time allowed, pass the HSFY papers at some point, and have a competitive weighted GPA.
Another thing to think about is what went wrong. If you a hard working student, that's great, but this could be a good opportunity to reevaluate your study methods or exam technique, depending on what you think happened.