If nothing appeared in EITHER window, it means your urine was not concentrated enough. Don't throw away the first test; you can use it again tomorrow morning. Don't drink a lot of water before bed. When you get up, collect urine in a container (like a yogurt tub that you have washed but don't want to use for food storage
) and dip the test stick into it for about 30 seconds. That's what the toll-free # told me to do when that happened on my very first preg test. If it still comes out blank, you must have a defective test. The "control" window should always change.
If this one comes out negative, I'd wait a full week to test again.
Hope you get the result you want!