The 1600 calorie Diet

I am currently trying to stay on a 1600 calorie diet and I feel like I am being deprived.  I feel weak and tired.  I also feel empty.  I don't like that feeling.  I hate that gnawing feeling in my stomach.  That is the feeling that makes me feel like I need to eat.  I don't know how people handle that feeling.  I have friends who are really thin and I can tell by what they eat every day that they probably eat about 1400 - 1600 calories every day.  Do they get that gnawing feeling every day and ignore it or do they get it?  Do they feel weak and empty or are their bodies just different? 
At least I have the summer to "suffer" through this part of it. I know it gets better in a few weeks.  I am hoping by the time I go back to school in August my body will be use to the neglect.  I certainly couldn't teach the way I feel right now, I would have to eat something or my students would get one grumpy teacher!