I think I see what the problem is most of the breakfasts you eat are mainly processed foods with little to no nutrients (with the exception of the banana) is the oatmeal the instant kind out of the box? you should try making oatmeal with steel cut oats it makes a big difference on keeping you fuller throughout the day. a bagel thin/ww bagel is bread but its stripped on the essential nutrients. and anything that says "enriched" in the ingredients is not real food as welll.while in a perfect world its super hard to eat non processed foods it is possible. switch the bagel thins (processed) with the cream cheese(processed) for egg whites with veggies in the morning and you will see how you will be fuller longer
skip the lean cuisines as well they are loaded with preservatives and sodium...try making grilled chicken on the weekend cut it up with celery on eziekel bread. or get honey roasted turkey apple and sliced avocado on ezikele braed it will keep you fuller longer.
Good point about eating less processed foods. I find that if I eat a cereal high in fiber like frosted mini wheats, and I've just tried a Kashi cereal they tend to keep me fuller longer. I also stretch out my meal for instance I ate my banana when I got to work, I just now finished my cereal, and if I'm hungry later this morning I'll eat a yogurt. I've recently have been eating Greek yogurt which is high in protien and that really is helping.
Lunch today is from the cafetria its a Strawberry Chicken Flat Bread Salad, it's lettuce, strawberries, blueberries, manderin oranges, sprinkled with a little coconut, oh and grilled chicken. I always ask for the dressing on the side I don't like a lot of dressing. They serve it with a piece of flat bread its more of a thin crisp cracker with cracked pepper and sea salt. I know this will last me until dinner.
Snacking at night is not a problem for me either, I'm not a snacker don't like chips ect.. If I do want something I'll have popcorn or fruit or string cheese.
For me it's the morning that is hard to get through, because I start so early (5am)

and I'm hungry when I get here most mornings. That's why I stager my morning food.