Did I just not ovulated ?

Va

I have a 27-31 cycle (usually it's 28 days). I had a very strong peak last month on CD16, while my previous positives where on day CD13. This month it seems that my highest levels where on day 13 but not high enough, and after that nothing (neither on 30th or today). Is it possible that I missed ovulation ? Or does liquids intake dilute the urine that much ?

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