Why would any right thinking Health Professional say anything to a mum in your position other than "That's fabulous - you are doing a great job" Unless it was to say "You must be so proud of yourself" and "Keep up the good work"
Can't help betting this same person would also be on the case of a mum whose baby was only gaining smaller amounts - saying "he needs more"
You are doing a beautiful job. You are right - you can't over feed him. But, stop stressing that your milk will drop off - it can't happen. You feed - you make milk - pretty much all there is to it