New here....help!

Mistyglitter

I've been using MFP for 3 weeks. MFP suggests 1200...I didn't think I could do that, so I've been doing 1500. In 3 weeks of meticulous calorie counting and eating back exercise cals, I've lost only 1 pound. I could just die.

I just did this: http://iifym.com/iifym-calculator/ calculator, which places me at

BMR 1639
TDEE 2254

I don't understand the difference between these two, but okay.

Aggressive Goal: 20% 1803.

Should I really increase to 1803?

Thanks.