I am on Day 10. It is not my first time doing a VLCD, and I can tell you the first few days are quite tough and can make you moody of course - you have gone from having whatever you wanted whenever you could to virtually nothing. Takes a lot of will and determination jut to do that - add any stress etc and it can affect your moods. But you get a pass.
I hope by now you are feeling abit more in the groove and are in full ketosis and starting to feel happier. I am finally in ketosis, and that feels like a lifesaver to me - its all easy from there.