This is a thyroid forum, so you really should ask your question on the Gallbladder forum, which can be reached via the following link:
http://www.medhelp.org/forums/Gallbladder/show/1208
I can tell you from experience that gall bladder attacks can take different forms.
I used to get really sharp pains in my right side, right under my rib cage and over the period of several hours, they would gradually move on down and eventually go away... felt like gas pains. I didn't lose any weight and I didn't throw up. I happened to have a very large stone that would lodge in/near my bile duct and partially block it, which is what caused the pain.
If you haven't had an ultra sound, you need to get one. I've never heard of weight loss being a gall bladder issue, but that's not to say it isn't. Get checked for diabetes while you're at it.
The gall bladder is on the right side, so if your pain isn't on the right side, it's probably not gall bladder.