low amniotic fluid

Hj
Baby's till measuring 4 weeks small and my amniotic fluid has dropped from last week to this week I'm now at a 2.7. Im 35 weeks pregnant and I have an ultrasound on Tuesday to check if It my amniotic fluid is still dropping followed by a NST which he passed last week . Anyone one experiencing the same thing ? Did you have to deliver earlier ? This is my second preganancy and my first was a premie due to water breaking at 34 weeks and 3 days in labor . Anyone else? Should I be worried 😩