You will have to wait until the court sentences you to know whether you will have to resit your driving test or not. In some cases, you are just disqualified for a certain amount of time but if the judge thinks your case was serious, then he can order that you retake your driving test before you're allowed to drive again.
Regarding your HGV entitlement, here's what the Highways Agency says:
If you receive a ban for drink-driving while driving an ordinary motor vehicle, you will also lose your LGV entitlement! And there's no guarantee your entitlement will be given back when your car driving ban comes to an end. The Traffic Commissioners who regulate Goods Vehicle Operator Licensing have the power to extend the period of the ban to stop you driving for a living. They can remove your vocational entitlement (your HGV licence).
When you receive a driving ban, it applies to all categories that you have on your licence and for you, it means you will lose your HGV entitlement.
You can find more information here : Highways Agency - Driver Impairment