Baby super low??

I had an ultrasound the other day and the doctor didn't do any measurements or anything but she said the baby's head was super low, however didn't say she was concerned. Three days later I'm laying in bed and I just feel twinges near my cervix and vagina when she's moving around, and not kicks in the ribs anymore.  Is it paranoid to feel like she's getting ready to be born soon?? Or is it normal that she's so low already? 31 weeks