Hi there guys. My last period was on the 5th July and on the 27th July, i noticed brown spotting when i wipe. This happened for a day and on the next day I bled a little, and the next day, a little more. I am relieved as i think this is my period, however, today it stopped. My usual period length is about 5 days. While this month its been 2 days! This has never happened to me before, and yes i have had unprotected sex this month while i was on my period (8th June). I also had a pregnancy test on the 28th which resulted negative. I took my first ever birth control pill on the 28th as i thought it was the first day of my period! But now i am in doubt as it might be implantation bleeding?? I am sure neither me or my fiancee has any sexual diseases. What should i do? should i take another pregnancy test? or check if i have any diseases?

Help please! - Stressed :(