Congrats on your weight loss so far - I'm sure that makes you feel good! I would say 1000 calories is not enough, especially for your height and weight. Sometimes when we dip too low, our metabolism slows and tries to hang on for dear life. Of course, if you stick to 1000 calories per day, you will start losing again, but I don't think you could keep it up forever, nor do I think you could have a nutritionally sound intake. Try upping it a bit with greens with a healthy oil dressing, or a serving or two of nuts - not very filling, but healthy calories. My guess is you should aim for at least 1500 calories per day, and you would start seeing losses again