Hang in there! It'll get better. The rumbling is most likely the gas. I had that, 5 days out its pretty much gone ...I think mostly because I'm moving as much as I can. I know everyone says that but it works.
For the Water and diet, seems like everyone hears something different. I was told min of 64oz of water per day (Protein shakes, popsicles, Jello count too) and min 60 g of protein per day. So for my Protein Shakes that's 2.5 scoops. I sip constantly water or shake all day to stay hydrated.
I totally get the sight n smells of yummy but bad food. I just remember it took me almost a year to get here and I'm not going back now!