Hi, very best of luck, let us know how you get on! The best pieces of advice I can give are:
1: at the point you go into yout viva, remember that nobody - repeat; NOBODY - will know more about your topic than you. Sieze that thought and feel confidence
2: don't assume that every question you are asked pertains to a weakness in your thesis. Even if your thesis is perfect in every way, an examiner still has a job to do, and some questions may be just simply because they are genuinely interested.
3: enjoy it if you can - I was a wreck before mine, but as I got into it, I enjoyed the conversation. You'll never talk in depth about that piece of work again so make the most of it.