No such thing as starvation mode, at least as you're thinking of it. Where exactly do you think the energy comes from to keep you alive? It's completely against the laws of thermodynamics. A calorie is just a unit of energy.

When you count calories, do you:

1. Count EVERYTHING. Every single tsp of oil, every spread of butter?
2. Do you do this for at least a few weeks to a month (due to water retention, bowl movements
3. And finally weighing yourself every day, to get most accurate measurements (due to fluid and shit fluctuations).

If you eat a 1000 cal a day for a month and don't lose a reasonable amount of weight, you need to see a doctor, or a university or something.