Spotting question

Well I'm 12dpo today. Took my temp this morning and my temp drop from being 98.0/98.3 to 97.6. I had very heavy thick cm all the past couple of day with today feeling I started my period. My boobs have been hurting since the beginning of the week, I've been extremely tried and sleeping all the time and have been getting heartburn and vomiting a couple of times. Question is when I went to the bathroom this evening when I wiped I saw pink blood on the tissue. I have been having dull cramps all even. Is this implantation bleeding or is AF coming? Thanks in advance.