1. You may want to cut down on your overall intake of soda - diet soda, while it doesn't have any cals, tells your body that "sugar is coming", so the natural response is to store as many calories as possible. Like, diet tricks your body, and then you end up absorbing more cals from other food you wouldn't otherwise absorb as readily.
2. Figure out your BMR (the calories you burn if you spent a day in bed). There are tons of ways to do this - just look online. From there, it's simple: BMR + exercise cals - food intake = calorie balance. 3500 calories = one pound of fat, so adjust your intake accordingly. A small thin female might have a BMR of 1800 calories in a day, while a large male might have something more like 2900. Find your BMR!
Sorry for all the technical junk - I'm kind of a health freak!
3. Are you on HRT? Give HRT like 12 months - you'll be pleasantly surprised how much your face has changed!
I wouldn't worry TOO much about the Red Bull - society has had a way of demonizing energy drinks with no real basis. Sure, a caffeine-free lifestyle is best, and nobody would argue with the fact that drinking 5 energy drinks probably isn't the best for you, but I've found the people that give energy drinkers the most grief tend to do it while holding a coffee cup in one hand. Yes, coffee, ounce by ounce, has more caffeine than most energy drinks, and energy drinks are fortified with B vitamins and amino acids. It's obviously not the best thing for you, but don't give in to a lot of that anti-energy-drink hype.