Take your holiday and have a great time , you deserve it and let's face it , it may well be your last bit of freedom for a looooooooooong time. Take it from someone who knows lol. I take it this is your first baby ? Congrats. Oh and I wouldn't worry too much about the weight of your little girl until she's here. Just keep eating well and avoiding the usual things you can't eat and that's all you can do. What will be will be.
When I was pregnant with my eldest daughter , my midwife and doctor kept telling me at appointments that I was going to have a very low birth weight baby and that I was measuring two weeks behind the normal size. I was devastated and blamed myself because although I ate really healthily , I had terrible morning sickness right through my pregnancy and blamed myself. Then at one appointment , a different midwife told me that they were talking rubbish and that she was lying low in the pelvic area and I probably wasn't carrying a lot of fluid - hence my petite bump. She was 7 lb 14 oz when she was born which is heavier than the average birth weight (although light compared to my other two who were well over nine pounds ) and at nine years old , she is very tall , wearing clothes for aged twelves and is very fit , so don't worry too much , they don't always get it right and even low birth weight babies can shoot up in height over the years.All the best and remember and come back and tell us what name you pick and what weight she is etc x