No I think it's just acid reflux brought on by anxiety.
I had this last year and convinced myself it was something horrible and it was all down to my stupid anxiety. If I get anxious now I get stomach problems and the burping is all anxiety related too. If you just try and relax and get busy doing something else I'm sure that everything would settle down and you would start to feel better.
I don't know what Prevacid is but I was prescribed omeprazole and I took one everyday and after a week or two I started feeling better and I don't need to take them now unless I get anxious again and it all starts up again.
I think your doctor probably just mentioned stomach cancer because he thought that's what you were thinking rather than thinking you might have it.