Sick/weird feeling when stomach is empty???

For the past 8 months I have been experiencing a weird sensation when my stomach is empty or I haven't eaten in a good period of time.

I don't know how to explain the feeling. It is not hunger and is not really pain.
It is rather uncomfortable tho. 

I guess the best way to explain it is a slight pressure sensation right where my stomach meets the esophagus. It can kind of feel very slightly nauseating as well.

The second I eat anything it will instantly go away...

Does anyone have any clue what this could be and what causes this?