Confused and unsure

Had my first real fill three weeks ago, for two weeks had alot of trouble with food, would eat to much - not really knowing I was eating to much and throw up the last few bites. Monday visited with surgeon and he agreed that it was a learning curve. Had not lost anything in two weeks. Started drinking more water as recommended and was doing much better, then today all heck broke lose, I would have and could have eaten ANYTHING. I did actually, I ate an entire steak, this is not normal for me, usually very little meat if any, after I finished was extremely full but that was all. Since drinking the water, did lose 3 lbs, which I am sure is water weight. Why can't I get full now, others tell me they can only eat little bits and small portions I eat smaller portions but fairly normal size bites. Am I doing something wrong???