I'm two months post op and still experiencing nausea at various time of the day. I recently noticed that its worse when My stomach is empty (when I get hungry).

Has anybody else experienced this or is it all in my head?

It is not in your head. I have experienced the same thing, it only started recently and I am almost 5 months out. I also noticed that it was normally right before I went to bed as that is usually when my sleeve is empty as I not a big late night snacker.

Fiddleman has a Protein shake he makes that is an extended release protein. I got some of that and do one of those about an hour before I go to bed and the problem went away. If you look in the Fitness and Exercise section for some of his posts you will find it. I am at work or I would link it to you!