I am new here and I am starting my 3rd week of IP today. I agree its easier to drink all the water I need while at work, during my two days off (sundays and mondays) I find it harder to drink all my water or stay on a schedule but I still try to have my 3-4 protein packs a day. Thus far I've done good, and the cravings do get better, at least they have for me. I don't even think about cheating, I more worry about whether I can eat on time lol. Keep with the IP, its so worth it, a friend of mine that recommended has already lost 40 lbs in 2 months and she looks awesome!
Btw, what I think helps, with any program but definitely IP, think about weekly goals. Instead of saying I have 50-100 pounds to lose, think about it weekly. This week "my goal is to lost 7 lbs or 5 lbs or whatever your goals is" and stick to that each week.