Starting my period or implantation bleeding?

Most of last week my CM was normal- white and creamy. Then it got clear and stretchy like normal. 4 days ago this little squishy tan/yellow clump thing came out on the tissue. 3 days ago up until today it's been clear and stretchy like normal, but a dark brown color mixed in with some of the clear. It's odorless and not heavy, very little amount. Then after I wipe a couple of times again, it's like normal, but different CM- watery and clear. Also when I woke up this morning there was dried up dark brown flakes sticking to my panties. What does this mean? I shouldn't start my period for atleast another 5 days or so. I don't remember my CM ever being dark brown almost a week before my period. The last time I had was 14 days ago. Is this an early sign of pregnancy? What does CM look like 2 weeks into pregnancy? Also, we were each other's firsts and we've only been with each other, so I'm positive it's not HIV or a kind of STD. Thanks!