38 wk appt,..

I had my ultrasound at 36 wks, 2 weeks ago , so that means ive had 2 appts since then and they just told me today At 38 wks that my fluids low & im measuring small, and ordered me another ultrasound 5 days before my due date for next week. After the other 2 drs ive had including the ultrasoundtech  said im meausring perfectly on track.. Just frustrating doing all this for the first time, youjust  want everything to gosmoothly 😩 anyone know why your fluid gets low and if theres anything you can do to raise it??