I took my first Depo shot March 30th of this year, on april 1st (2 days later) I had a surgery and was on strong antibiotics, I was told it takes about 7-10 days for the shot to become effective, so would taking medicine such as antioboiotics (which elements the effectiveness of birth control) cause a problem with my shot becoming effective? I still had a period at the beginning of May (around the week of the 8th) which I was told shouldn't happen once the shot is leveled out in my system. and my boyfriend and I have had unprotected sex and he actually finished inside of me at the end of May, should I be worried that I could be or become pregnant?