To be honest, you won't like my suggestion. But I'm gonna give it anyway.
Switch to decaf coffee and cut out the Dr. Peppers.
Told you that you wouldn't like my suggestion. But here's what you do instead. Switch to a high protein breakfast. And I mean high protein, like 30 grams of it. Oatmeal provides fiber as well as protein, and several eggs together with the oatmeal. You can use one total egg and several egg whites if you are worried about calories or cholesterol, and you can cook raisins in the oatmeal to make it sweet. Don't use the instant oatmeal because it's not as good for you. Only put a tiny bit of milk in it after you cook it to cool it down, and don't put sugar in it.
The protein will keep your blood sugar level in the morning so that you don't fall off the cliff. Eat a few snacks during the day with protein as well - low fat string cheese is an excellent choice. Greek yogurt works too, but you have to look at the ingredients to find the highest protein amount and lowest fat gram and sugar amount - they tend to vary widely. Also cottage cheese (choose the lowest fat kind - I can't even taste the difference,) and I put sugarless apple sauce on top of my cottage cheese.
And most important with this? DRINK WATER. Half before noon, and the rest after. You need the water to flush out the extra protein. You should be drinking in ounces, at least half of your weight in pounds. Say you weigh 120 pounds - drink AT LEAST 60 ounces of water every single day. And if you are able to walk on a treadmill or in a mall everyday for an hour, you'd feel better too.
If you don't believe me, look at Dr. Oz's website. He said on one of his shows that a lot of protein with breakfast is KEY to feeling good and losing weight. I don't know if you need to lose weight, but you sure do need this protein.
It might take you a week to get over the caffeine fix - I promise you that you are hooked to it, so if you have bad headaches, just know that it won't last more than a week.
I hope you'll try this.
Good luck,
Dawn