increased fetal movement a sign of distress?

Currently 36 weeks, as of 9pm last night my baby has not stopped moving AT ALL, not even for a few minutes. I'm so miserable, exhausted and it's incredibly painful. But I'm curious, since this is out of character for him, should I be concerned he is in distress? I'm already having weekly sonograms to check his growth (he's measuring below the 10th percentile). He's currently head down, no problems to date with fluid.