Terribly sick at 11dpo and today I feel great! What gives?

Jane
Starting at 8dpo I was feeling really crappy. Mainly fatigue and upset stomach. 
In the middle of the night at 10dpo I woke up with a burning sensation below my belly button. Extremely weird but fell back asleep. 
Fast forward to yesterday (11dpo) and I left work early because I felt so awful. Mainly feeling sick and also warm, almost feverish. I got home and breasts and nipples started to become extremely sore. Areoloas were dark, couldn't wear a bra and everything was swollen. 
I had a huge bout of hormones rush through me yesterday and felt moody. 
Now today, I woke up feeling great, no symptoms, boobs feel and look fine. 
What gives? I tested today at 12dpo and bfn
I'm so confused! This isn't normal before af. 
Thanks for any advice!