Just ease my mind

I had a chemical pregnancy last month. My husband and I decided we wanted to try again this month. We tracked my ovulation and did everything we were supposed to and have been getting negatives still. My AF is tomorrow and I am praying it won’t come. I guess my question is: Is it possible to still get a negative the day before your period but still be pregnant or should I just pack it in for August? You would think after two babies I would know this but I’m just so stressed and full of anxiety and the blues.