Started ttc in early August. Right off the bat I had sore boobs, heartburn (weird), and finally 3 faint positives. Very excited and then got AF on scheduled arrival. Chemical pregnancy?

So this month, fertility peak was 9/23. BDed nearly all of the green days. I'm already getting the sore boobs and heart burn again. Could anything even happen that quickly?? I've never had these symptoms in my life except for when I was PG with first baby 3 years ago.

Anyone have answers as to what might be going on? Can you even conceive that quickly after a chemical PG? Symptoms this soon?? So Confused!