Me and my boyfriend have been sexually active the past couple of months. We've been very cautious, using condoms all the time considering I'm not on birth control. The past 3 months my period has been every 19 days, and its been 40 days since my last period, june 1st. A couple weeks ago I went to the doctor because I noticed fishy smell etc. and was diagnosed with bacterial vaginosos. Was prescribed Metronidazole twice a day for ten days. I also had my doctor take the pregnancy test and it came out negative on june 29. She said it was too early to detect anyways. 4 days ago I noticed dark brown thick discharge with tissue. Had unprotected sex 3 days ago, took the plan b one step pill after i took another test yesterday, July 8th, came out negative. Then I had unprotected sex again today but haven't taken any medicine. Is it safe to take another plan b one step pill? I know I shouldn't but I would like to know either way. Also, why is my period late? Could I possibly be pregnant just haven't shown on the tests?