Weight loss: getting it right...?

[woohoo]

Over the last month I've joined the TE weight loss thread and started weighing in weekly. In 4 weeks of watching what I eat and exercising, my weight is basically the same (within 1lb). It's consistent through the day, too.

Now I've done some (very geeky, sorry, graph attached) number crunching on my calorie intake over the past month, and am beginning to wonder if I'm not eating enough... Seems ridiculous since I'm trying to lose weight, but looking at the last month's intake & output, my average calorie balance has only been 1200 per day. Looking online tonight, with my exercise level and base metabolic rate it seems like I should be eating closer to 1800-2000 calories per day.

Am worried that if I eat more I'll put on weight rather than staying the same, though, especially since my calorie balance seems to be pretty erratic. Anybody been in a similar situation? How did it work out? If I did start eating more, what type of food would be best: carbs/protein?

Thanks, woohoo

edit: should have said, I've been using the livestrong calorie tracker and aiming for 1629 calories per day.