If you are new to tracking, are you sure you are only getting 800-1000 calories?
I recommend starting off by weighing everything for a few days. If you are estimating by sight, some people are very surprised how tricky it is to estimate portion sizes.
Make sure you know what is in everything. For example, some restaurants put oil or butter on vegetables and you don't know it.
Also, make sure you track everything that goes in your mouth. Those little harmless bites here and there can add up! (If that applies to you, of course.)
Just some ideas! Of course, if you are actually eating 800-1000 calories a day and burning 600, I would take the comment about starvation mode to heart and add in some healthy calories.