lmazy1,
As we become more adept at managing our day time challenges, sometimes anxiety becomes opportunistic and has to find sneaky ways to try and get a foot in the door...
...and often our sleep state leaves us vulnerable.
Use the same coping skills that work for you when awake...practicing before you lay down to take a nap, and of course if you wake feeling anxious.
With time and continued practice, this will start to become less of a problem, just as it has during your waking hours.
Peace and progress!
S.C.