
Try not to go below eating ~750-1000 calories a day if you’re doing calorie tracking for a deficit, your body does in fact need a certain amount of new nutrients to stay healthy and fully functional. If you want to track your weight while you do so, measure once or twice a day under similar conditions and don’t focus on the actual number you see, but trends in the numbers over time. Your body weight constantly fluctuates depending on how much food and water is in your body at the time
You will also most likely see better results if you are able to do exercise as well, even light exercises will help as long as you get yourself moving. You can safely lose 1-2lbs of fat a week, I’d recommend aiming for 1.5lbs at most (3500 calories = 1lb of fat). Losing 20lbs in 2 months is a little more than I’d recommend, but if you can make good lifestyle changes you will lose as much as you plan for, but would take slightly longer at about 3.5 months