TMI!!! But I'm confused! Pictures included.

Noemi
I have been charting my temps and started using opk this month. I got what I thought was a positive opk on Monday CD 20 but for the last two days I have been getting a pink discharge when I wipe.. Can someone tell me what it might be?? It can't be implantation bleed, it's too early. Thank you!! 
I discarded the crazy temps and this is what I got..