AF hasn’t shown up


AF was due today..took a test and got a bfn. There’s a chance we may have had a chemical last month. We took early tests last month and had two tests that had super faint positives but we took more the same day Bc we wanted to know for sure and had 3 negatives so we’re unsure. My period did come on time despite those tests last month..I’m NEVER late. Any thoughts or advice?