Hunger, the inner diva??

Ok, I am about 10 weeks out from my RNY.  Feeling great and have had very little food issues.  I don't ever feel hungry at all, but what I have been noticing is that my mood shifts from pleasant to something reminiscent of a ill-tempered diva if it has been more than 5 hours since I ate.  Once I do eat I am back to my pleasant self. 

Does anyone else have this drastic change in mood with hunger?  My husband and I are pretty much deducing that this is my hunger indicator instead of my tummy.

Early out, I seemed to just get empty, not really hungry, just empty.  I'm better about trying to eat every 3-4 hrs now.