36 week growth scan

Baby is head down and measuring BIG at 7lbs 6oz... wow! Last check said his head is in the 95th percentile... so it looks like we're going to have a big boy! Dr said the amniotic fluid was a bit low, but still in good range- but that I should be drinking twice as much water. I feel so bad now! Anyone else with possible low fluid? I think I just need to hear that it's fine as long as I start drinking more water.