Okay my last period started December 27 and ended January 3rd. Me and my boyfriend had unprotected sex on the 4th, 5th, and 6th. Based on an ovulation calendar I was supposed to start ovulating on the 8th. I could obviously tell I was fertile on the 10th (had a lot of discharge). We had unprotected sex on the 10th too. On the 12th I had some light brown and really light pink spotting (I hardly even noticed it at first), then the next day the blood was extremely dark brown and a little heavier (only enough to need a liner), today it was dark brown and light then it got a little heavier and had some bright red with it as well. A little while later the blood was bright red and slightly heavier, since then it has gone off and on between really light pink bleeding and dark brown and bright red bleeding. My period is almost always regular and it shouldn't be starting until the 24th. The bleeding is nothing like my period (I bleed and clot a lot and reallllly heavy for 8 days whenever I get my period). I can see tissue in my red blood and dark brown blood but not a ton. I have been more tired and get tired quickly, I have some back pains, and need to use the bathroom more often than usually. So my questions are can implantation bleeding come and go? Can it be bright red and go back and forth between brown and pink as well? Based on the symptoms an bleeding do you think I am pregnant????