What’s this???

Does this look more like the beginning of a period or implantation?? I felt a lot of discharge so I went to the bathroom thinking I started my period, and it was this. I put a tampon in for the rest of the day which was yesterday (12.12.17) and when I took my tampon out it was completely white. I do have unprotected sex but I’m on the pill, I’m only worried because I’ve been taking my pill late off and on over the past month the lastest was 11 hours

UPDATE: Today I am experiencing brown blood mixed with clear discharge