when you just know...

I'm a nurse. and I know my body pretty well. I've been TTC for 8 months now with my bf. this cycle. Glow said I was due to ovulate the 16th, but I ovulated early per opk. we did the deed. around the 19th I started spotting. first it was reddish, now... three days later... it's brown. not enough for a pad, but when I wipe it's there. sensitive to smells. sleepy, but I've been working more... so it's possible that it's work. my womb feels tender and swollen. and I just feel like there's something there. I'm getting little twinges. I tested negative on an FRER this afternoon with non FMU. I knew it would be negative, but I did it anyway....hoping. AF isn't due until 31st. I just feel like there is something there.... all my months if trying..... I've never felt this sure.