what could this be? please help and comment ty

Cycle day 16 and 17 yesterday and today down there has been damp. When I checked it was just water like discharge no color and odorless. eve says my fertile window should start tomorrow. I had two periods the same month so I don't know how many dpo I would be. My first period was Oct 7 through Oct 8 th then ended. Then my next period was Oct 21 through 27. I been ttc so when I only bled on the 7 th and 3 hours on the 8 th I thought of breakthrough bleeding. But i got a negative on a pregnancy test so it wasn't. Then that's when I got my second period. I had unprotected sex on Sep 11,17,19,20,23,26,28 and 29. I also had unprotected sex on Oct 3,10,12,18 and 20. Do I count dpo from the first period or 2 nd. Could this be my fertile window or ovulation?