No lie!!! Your story, is my story. My Fiancé and I have been trying for months. I too estimated my fertile days to be Aug 4th to the 7th. I used another one to see if they'd say the same thing and it said I would be ovulating on Aug 3rd to the 8th. We did our 'baby dance', on the 4th only.
I was supposed to start my period on the 19th of Aug. It's the 24th and I still haven't started. I'm on a 28 day cycle on the dot every month. For example, my last 3 menstrual cycle has been 5/30, 6/25, and 7/23 . I am not having any real signs of pregnancy too. And..I too, I have been getting the dizziness though, any time of day when I stand up, and I've tried standing up slow but I still get dizzy.
The thing is that I we are much older. I am 41 years old, and I have felt this way before once in my life time. I period was late more than 7 days, and them BAM!!! it decided to pop-up. I guess I was going through a period of being stressed. Either way, I was crushed. I said that I would give it until Friday, 8/28/15 to see if anything comes down.
If not, I was going straight to the doctor. I hope everything works out for you. As for me, I am going to wait until this Friday to find out.