which scale is right and eating disorder

Question
Hello. Well i have a few questions.
First is, at the gym scale I never loose weight on it. And it always makes me about 6-8pounds heavier than my digital Weight Watchers scale at home. Do you know which scale is more accurate and which I should believe more so?
Also, I have been bulimic for several years...
When I binge, and eat hundreds of calories of carbohydrates, I don't actually throw up ALL of the calories I eat, is that correct? If that is true could that be why I have gained weight over the past few weeks since I have binged and purged every day? How much do I actually throw back up?
Do you have any advice on things I can do...eat..drink...to help curb my cravings?
Also I have been working out with a personal trainer for the past 2 months or so. We do weight training and I do cardio. I also try not to eat too much during the day and keep it low calorie and healthy. If I control my nutrition, should I loose weight and not only gain muscle by doing this?
Thanks so much.
-Karen

Answer
I'll do my best to answer your qs, Karen.
First, you say you never lose weight on the scale.  You don't say if you are normal body weight, or even under weight, so not losing weight is not always a bad thing, particularly if you don't need to!!!!!
As far as which scale is more accurate, the only way to know is to go to one of those scales at the grocery store and weigh yourself.  Those are calibrated and usually fairly accurate.  As far as your actual weight, it's not as important as your body fat levels, unless you are extremely obese.  You can be "normal" weight, but still have dangerously high body fat levels, and a crappy diet and unhealthy lifestyle practices, so don't rely just on a scale to tell you information about your health status.   It's serves as more of a monitor about whether you are  gaining/losing, and your general mass.  It doesn't say anything about how much lean tissue you have (which is a lot more important than how much you weigh!)

When you vomit, you most likely are not throwing up all the calories;  that is correct.  And when people binge, it's usually on sugary sweet, highly refined snacks, that will quickly digest and pass into the intestines.   Yes, if you have gained weight, it's due to the high calorie content from your binges.
A great way to help curb your cravings is to eat small mini meals throughout the day.  Always try to include some veggies and/or fiber, as well as lean protein and whole grains with every meal.  For instance, don't just have some whole wheat crackers as a snack....add some low fat, low sodium cottage cheese or no-sugar added yogurt, and some celery sticks and raw cauliflower .  If you just eat some carbs, you really won't be satisfied, and probably hungry about 30 minutes later, causing you to overeat.   Sounds like you don't eat enough fiber and veggies, as well as drinking enough water.  If you do this every few hrs, you shouldn't have these intense cravings.  You most likely aren't eating enough calories, which will cause your body to have voracious cravings.  You end up holding out and trying to resist, and when you can't resist anymore, you go on a binge, feel guilty and then vomit.  
The key is to prevent those cravings by eating those mini meals with the items I listed.  That is just an example, but I'm sure you get the idea.  
And yes, by doing this, you will keep your body weight healthy and lose body fat, while gaining muscle (and don't worry what the scale says...look in the mirror and look at your fat....does it look flabby and loose or tight and lean?  That is a much better way to gauge your fat levels).  

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