What is actually going on here?!

So I believe I O'd on July 25. Hubby and I had sex 23, 24, 25. I started taking tests at 7 dpo and started to get faint lines on the IC. They went away around 10dpo but then came back stronger around 16dpo. The thing is I never got a positive on a 'name brand' and even got a blood test which came back negative. I was supposed to start Aug. 8 so I am now over week late and now getting negatives. Anyone ever have anything like this? Or maybe Im just being crazy and overhopeful! Most of these tests were taken in the morning or right before bed after holding for at least 4 hours.