Hi Kristie
Your baby and you make fluid all the time although towards the end of your pregnancy you do make less fluid. Drinking plenty of fluids will help to provide more amniotic fluid, you should aim for about 3 litres a day especially on hot days. Did the doctor tell you what your AFI was? I would be interested to know. (Normal AFI is between 5 and 19) The only effect that a low amount of fluid will have at birth is that you birth passage may not be a lubricated as it could be and therefore increasing your chance of tearing and yes causing some increased stress for your baby. But for this to happen your fluid level would have to be very low.
To help increase your haemoglobin you should also eat red meat and lots of leafy green vegetables.
I hope this answers your questions.