Hey! Take a deep breath now. Ahhhhh.... OK, here's what I did. I took your height and weight, and assumed you have an age like 30. I entered this information into my FitDay program, and set your activity level at sedentary. What I got is that your everyday calorie burn, with NO exercise, is 1,744 cals. To lose 20 pounds in three months, you would need to drop your eating by 458 cals a day, average, so you would eat an average of 1,286 cals per day.
Remember, that's without exercise. If you were exercising you would have a bigger deficit, or you could eat a bit more than the 1,286.
If you are younger and even more active than sedentary, your burn level would be higher still.
I think you must have been looking at some pretty weird calculators!
Jay