I bought five tests. Four were negative. Two weeks after missed period I got a positive. Hcg levels may be too low yet.
Still possible to get a positive wait until the day your period is due
also if you call your doctor they can order a blood test to test the quantity of hcg in your blood. those tests.are.more accurate.
Try getting an ovulation prediction kit. That will tell you when you should be ovulating. Good luck to you.