There isn't really a should... for anyone. Everyone's bodies are very different. I can give you a "most people do...."
Most people seem capable of losing about 1-2lbs a week. That's AVERAGE, so you might lose .5 one week, and 2lbs the next...onward and onward...etc, etc. Most people seem to lose quickly the first few weeks. They're on the ball about what they're doing, their body is getting used to the changes, and is losing water weight.
Forget about what you did for breakfast. Put it aside. Have a plan for the rest of the day so that you're eating healthfully for your snacks and other meals