Ttc#6

Okay ladies I need advice. I found out I was pregnant last year around thanksgiving. It was a faint line I had us they said baby was small for gestational age. December 15 I had to have a d&c done so been TTC ever since. Well every month I think I'm preg cuz me and the hubby do the dance every other day at least. Well my AF started August 18 it wasn't like normal it was barely any thing at all then one sudden gush then spotting for 9 days. Well my ov day was sept 1 and we didn't have sex for 5 days leading up to that. Well sept. 5 we did the dance and there was some old brown discharge and very light pink streak when I wiped that stopped after. Now I am waiting on af to show on the 15. My question is why the faint discharge all a sudden never had this before