this could mean that you're going to go into labor soon. I am also 38 weeks and feeling distinctly nauseous.
Are you able to keep down liquids? If not please call your Obe urgently as you may need to be admitted for rehydration. Even if you can drink, better give your Obe a call asap to let her know what's going on and to get some advice.
Let us know how you go.
I agree completely with Super Sally. I too became very naseus toward the end of my pregnancy...it was actually even worse then the first trimester for me. I just want to reiterate what she is saying in the importance of staying hydrated. Please do ensure you are communicating with your OB. I wish you a healthy and safe delivery!! All the best to you.