Fundal Height

Hello everyone I had a question. I am a first time mom. My whole pregnancy I have had no complications. Myself and the baby have been right on track with measurements and weight until I got around 34 weeks. My fundal height has always been the exact number of weeks I was at the time of being measured. But when I got to 34 weeks my FH was 33 and now I am 36 weeks and my FH is 34. My due date is Dec 6. Doctor says this is normal. What do you all think? I have another appointment next week and will begin to be concerned if I'm 37 weeks still measuring at 34.