Welcome!!
The first three days are tough, but it's even tougher when you don't get in all your meals. Really try to have all 5 supplements and your lean and green every day.
At first when reading your post I was afraid you thought the crisps and crackers were meals - sounds like you know they're not, though. Make sure you don't treat them as one, though, in terms of your timing, like you did on day 1 (eating the crisps and then waiting 3 hours to eat again).
It's OK to eat more often than every 3 hours if that's what your schedule dicatates. Just go at least 1 hour between meals, and be sure to have your first meal within 1 hour of waking up. There's no reason to avoid eating in the evening with this plan, either, so if you're staying up late you can eat even a minute before you go to bed with no ill effects.
Are you getting in water? I aim for 3 to 4 liters a day, but that's excessive for some people. It really helps with the hunger, though, not to mention how great your skin looks when you're hydrated like that!
Keep it up!! You will feel great in no time, and the weight will come off too. I am a bad example lately but I do know what I'm talking about.