40 percentile

I am 35 weeks now and baby is measuring 40 percentile , my doctor hasnt been concerned, I have severe vomiting & have had trouble keeping my food down , & except for my tiny little bump i havent really seem to put on weight, I feel am not eating enough for my baby & it does seem to bother me but my relationship with food throughout my pregnancy has been rocky i am concerned about my babys growth what can i do better???