Hi,
How are you?
Numbness in the head can be due to bad posture while sleeping. Numbness can be caused by twisting of neck while lying flat on the back.
Other causes can be stress, sleep deprivation, anxiety and sinusitis. Please sleep in the correct posture in order to avoid twisting of neck.
Also make sure you get 8 hrs of sleep daily. Hope this helps!
Did you ever find out what was wrong? I have the same problem