I Wake Myself Up In The Middle Of The Night

I wake myself up in the middle of the night swallowing. It's been an on going problem for the last cpl years, some nights fine, others are repeatedly interrupted by this insane swallowing urge. Sometimes if I massage under the back of my jawbone and drinking water it subsides but what in the world causes this?? The only meds I take is a BP and Antidepressant.