False symptoms - is it all in my head?

Hailey • 29 from Brisbane, having no. 2 (only 13 months after no. 1!)
I've been ttc for a while now and this month has been different. I started feeling different and I was getting a sore lower back, and sort of sharp pulling cramps from 7dpo every day and the last few days nausea and really sore nipples.  I usually get sore boobs before AF but not nipples. I'm now 13dpo and AF due in 2 days and still getting a BFN.  Is my body making these symptoms up?