I lost 30lbs since august what is going on? I am 20 years old. I just had gallbladder disease and had my gallbladder removed. I been having a decrease of appetite and loosing weight. Had colonsocipy and came back ok.

Hard to say. Why is your appetite decreased? Do you have a food fear, does it hurt to eat, do you have fatty stools? You are obviously seeing a GI doctor who should be asking these questions. Ct of abdomen maybe an upper endoscopy?
Please . Please call your primary care doctor and your gastroenterologist and schedule an appointment. It sounds like you have unintentional weight loss. Be sure you are eating 4-5 small meals a day and drinking plenty of fluids. Take a note of your initial and recent weight to the doctors appointment with you. If you have fever, vomiting, pain, or new symptoms then you must go to the emergency room.