Didn't want to read and run. Firstly, I don't think that was very good for them to tell you that over the phone, most places will have a face to face discussion. No, I don't think you should be petrified but can fully understand why you feel like that. The good news is that they think they got it all, they wouldn't say that if they didn't think it was true. It sounds like they are doing a cone biopsy to be absolutely sure so please be assured everything is being done for you.
Try not to worry too much, good luck for next week and let us know how you get on.