I had a very similar experience to yours in 2009. I have had gastroparesis since February, 2008 and was finally correctly diagnosed with it in January, 2009. However, my gall bladder was basically dead so I opted to have it removed in September, 2009. During the first two weeks post-op, I was sick as a dog... throwing up a lot and very nauseous. Then, I quit taking Percocet and within 24 hours my GP symptoms were gone! (Narcotics make gastroparesis MUCH WORSE, but nobody told me that, I had to find out for myself.) Anyhow, for the first time in almost two years, I was able to eat real meals and gain weight! (about ten pounds)
Unfortunately, the good times didn't last. A few months later, my GP symptoms returned (fullness, abdominal pain, bloating, a little nausea) but I was able to hold my weight and even gain another five pounds in early 2010. For the rest of the year, I did okay but basically lost that weight back.
How are your GP symptoms now? Still gone, or did they come back? Also, do you find your symptoms are worse in the winter? That's been the pattern for me.