[Quartet]

Yes, wait.
Don't stress yourself, it will only stop your period from coming. You can also put your body in a state that believes its pregnant if you continue to stress on it.

I'd say wait the two weeks and take the pregnancy test at LEAST 3 days before your missed period, this will ensure you the best results. It's best to do it after a missed period, but I understand the anxiety.

Accidents are always possible. Just try and be more careful if you want to prevent a pregnancy.