Low amniotic fluid level? Anyone with experience?

I read a normal AFL is 8-18. Mine is 6.05 and I have to go back in 2 weeks for a recheck ultrasound. What can I expect if I’m still at that number, possibly below that number? I’m due Jan 31st so I’m 28 weeks 4 days. I’ve never had this happen and it’s baby #4 for me.