Non Positive Normal?

[MzKBailey]

Ok so I have posted a few other threads about Femara and Shot combo. So I was told that when I had timed ovulation (Which was February 18th) my pregnancy tests would be positive for a while. I was also told that is normal as expected and to wait until March 4th to take a real test. Now my question is, is it normal for the tests to go negative as the date gets closer, or is it a sign that the injection didn't work? I'm trying to be optimistic and keep telling myself that Wednesday when I test, it will be positive but, the negative strips now are making me nervous.