I don't think any birth control is 100% effective (other than abstinence) so it's possible to still get pregnant.

I don't know about the time thing, I think as long as you take it every day that it should still work. Judging by your title, it sounds like you do take it the same time every day, so you shouldn't have to worry about that.

Birth Control also can mess with your system too, maybe you're just late or something. I missed entire periods twice when I was on birth control. If you think you might be pregnant, schedule an appt with your doc.

I doubt you are pregnant with 2 negative tests and taking birth control. You can always continue to test if you think you are pregnant. Or you can go visit your doctor.

Pregnancy isn't the only reason women miss periods. Sometimes women don't bleed while taking birth control.

Like Ingi said, there's plenty of reasons other than pregnancy that causes missed/late periods. If you are just starting your BC, it could be your body getting used to it. You can see your doctor for a blood test if you are truly worried. Good Luck!