OK, so my girlfriend got the depo and 5 days later we had unprotected sex and I came in here a bit. Her doctor said the shot is effective immediately which I'm not to sure about with the stuff I have read about on the internet. Anyhow It was her first time getting the shot, and she had been off her period for over a week or 2 weeks. She has not had a period since, her doc said she most likely wont have a period. Now here comes my questions, we have took several pregnancy tests, one a one week 3 weeks, 4 weeks, and im sure more in there and all negative. Should I be worried? Should I have her take more of them? When would be the best time to get her a test for her to take. What would be the latest I could honestly say she is not pregnant? Thank you.