Hey Anothermatter -
1000 calories a day is pretty low, actually, and eating too few calories might explain your energy levels - basically, you need food to fuel you through your day! I wonder if you could give us a sample day of your plan?
I might try to up my calories by 100 or so a week until I got to 1400-1500, were I you, and see if that leveled out my energy and kept me more satisfied...try to eat whole foods (lean protein, fruits, veggies, grains, reduced fat dairy, etc) as much as possible and see where that took me.
Exercise may also help to moderate your energy levels - are you doing any now?
Hope that helps! Give us more info and we'll give you more!