Symptoms AF or Pregnancy?

Been TTC for 15 months now, each month I try not to read into my symptoms too much or get my hopes up. But I'm 12dpo today and AF is due in 4 days and I have never been early and last night I had a pink/brown discharge but no cramps, I've had a ticket dry throat and a runny nose since 7dpo and sore nipples since 9dpo, I've also got a sore back and I've had diarrhoea (sorry if TMI) this morning, ive eaten constantly since about 6-7dpo is this all just AF related or has anyone who actually got a BFP had these symptoms?

Thanks