I felt shaky, sicky, headachey for the first few days but after that I was fine (if you discount hungry enough to chew my own arm off!). As you are a few more days in, perhaps the milk diet is a red herring and you have a little virus or something. Maybe check in with your team if it continues as I have heard of the odd person discovering they are lactose intolerant during the prep period and feeling a bit rough. Hopefully, it will be over befor eyou know it! Good luck with your iminent ops people. x