Preston and his weight loss/gain journey

I will give you a quick back story then an update.

Preston was born premature and has had some stomach issues from the beggining. He spits up a good bit and always has. We had initially thought it would be something he would grow out of once he started eating baby food, but unfortnatly that hasn't seem to happen. He has also had a rough time gaining weight and holding his weight steady. We have tried numerous medicines for acid reflux and nothing seems to help it. Actually it will all help for a couple of weeks and then nothing. Since he has been born we have been for probably 5 weight checkups. Everytime the doctor says we will see how he is doing at his next appoitnment. He is meeting all of milestones on time, and he loves to eat so it is something we have tried to overlook. I know some people are going to think I am not feeding him, but I assure you he eats ALL the time. Thankfully that question hasn't even crossed my doctors mind.

We took Preston to the doctor Easter Sunday because he was weezing really bad and just felt icky. They determined he had an ear infection (fourth one now) and a bad cold. They gave him some meds and he seems to be doing better, but while we were there they of course weighed him. He has lost more weight. I am puzzled by all of this I don't understand how someone that eats all the time and can't even walk can continue to loose weight. He is a little busy body and constantly on the go, but really is that even possible? Well the doctor said at this point it is something that needs to be looked into further. He asked me if we would document everything he eats (food and formula) and if/when he throws up. He said he understands we can't really measure how much he throws up but document how often. He said he was going to talk to another doctor friend of his and give us a call on Monday to set up an appointment to come in next week. He said they want to take a look at his stomach and see what else we need to do.

I am sure its nothing serious, but naturally I am worried. I am hoping we finally get some answers and some medicine that fixes this problem.