Tmi question

I have a regular 28 day cycle. Today is day 21 and when I went to the bathroom this afternoon I noticed I had a fair amount of gooey brown discharge. I know it could mean my cycle is early, could mean implantation (hopefully) or could just be from sex yesterday (unusual for me). Wondering if anyone has any advice or experience to share? It doesn't smell funny or anything so I'm not concerned about anything major currently.