On your package of bread, it will say how many calories are in 1 slice or 1 serving, and then see how much they count as a serving. It depends on the bread, but 1 slice of white bread may have 70 calories. Usually, 1 large egg has 90 calories, and your cheese package will tell you how much in a serving too. For example, 1 american cheese slice (28 g) has 105 calories. So, if you used 2 eggs, 1 slice of cheese, and 4 slices of white bread would be 90+90+105+70+70+70+70 = 565 calories. You also have to count the butter or jams you may put on the bread, too. Every little thing adds up.
Seriously, use www.caloriecount.com and you can look up foods there and enter in what you eat for the day. Also, www.livestrong.com has a good website to look up foods too.
Look at the labels on your food packages, and they should say. If it doesn't, you can also look up these things online.
You also want to make sure to keep your fats down too. For instance, I eat fat free cheese slices, and they have 30 calories instead of the 105 that a regular 2% slice would have. I also eat whole grains and not white bread. Fat free lunch meats, milk, etc. They are all lower in calories, on top of the fact they are low in fat. Veggies have calories, but no fat, so they are great for you and fill you up. Fiber and protein help you to lose weight by keeping you fuller longer, and build lean muscle (which burns fat).
Please feel free to ask me anything about nutrition. I've done a TON of research on this.