The bleeding you had sounds like it is related to your new birth control. It is called break thru bleeding and can be normal during times of birth control start-up and changes.

If you had only been on birth control for 1 week then, yes, you could be at risk for pregnancy. By those calculations though, you would be due for your period this week? Next week? Wait until your period is due before taking another test. Continue taking your birth control unless pregnancy is CONFIRMED.