Oops! It is hard though at first so don't beAT yourself up. Firstly this hunger actually goes really quickly when your body goes into ketosis. Secondly, maybe have available something to eat in those weak moments that wont break your diet. A CD bar, or some protein or veggies? Its easily done, but the problem with things like bread it will take you out of ketosis or delay you getting into it. Avoid carbs at all costs! Getting through the first few days is the hardest bit, but the more rigidly you stick to it, the faster you'll get into ketosis. Also when you have a blip, let it be, don't stress just make sure to stay strong next time!
Best of luck, don't give up xx