Just received an email from my examiners offering me my viva defence in two and a half days' time. I had not started the preparation for my viva yet as was anticipating a much later date for it. For context I submitted my thesis some 3 months ago and although I feel I remember it I have not been able to devote the time to prepare for it. Do the 2.5 days give me enough time or should I ask my examiners if they are able to delay it a week?

I was preparing for my first year progression review and was trying to find a paper I had seen for my literature review. In looking I stumbled across a term that I had not checked before in my literature searches which lead me to a significant number of sources who had done roughly what I had done and had thought had been unique. What do I do and how do I tell my supervisor? My review is in a week. I had always maintained in meetings that I had been unable to find sources doing what I had done but that I wasn't 100% sure that I had not missed something.