Technically AF doesn't need to be late in order for you to test and get a positive. You say that you think you O'd between Aug 4-6 so that would make you 14-16 dpo right now. You can usually for sure get a bfp on a hpt by 15-16 dpo. I would say that if you wanted to you could test tomorrow am or if you are afraid of wasting tests wait until Sunday and test then. With my DD I got a bfp at 13 dpo and I just got a BFP today at only 9 dpo so you have a very good chance of getting a good result if you were to test tomorrow. Good luck!
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