anyone need US to check fluid?

Hi there just had my 33w visit and doctor is concerned I lost 4lbs since 9w's along. And says my uterus doesn't feel right? She was measuring my fundal height and says some parts feel high and some are low and the baby is in a ball only on my right side and thinks he's head down. She wants to know his size and amniotic fluid levels. Anyone have experience with this??? Kinda nervous now.