Jackie, what is your height and weight? You probably have a very low body fat. Maybe spreading your food out a bit more over the day would help. I have a huge breakfast round 7am or so and then usually go through to dinner - round 5-5.30 pm (my hubby is a shift worker who gets up at 2am for work, so we eat and retire early), with a very occasional snack (piece of cheese or ham or a handful of nuts) if I feel starving.
Do you eat much fat? Perhaps looking at that ratio as part of your total intake and increasing it somewhat might help.