How many DPO?

With stopping BC back in June, I feel like my body is finally getting back to normal. i had a natural cycle on Jan 24th-29th with using Provera or Clomid. So I can’t rely on passed cycles to determine O. So on the 5th I woke up to ewcm in my underwear. BD that night without any help with preseed. Then woke up on the 11th and when I wiped I had more of ewcm. Now I don’t have anything. Im currently on CD 20. I did do opk’s. Just want suggestions when I could start testing. Trying for our first. I’ve been trying to stay positive this whole time. Started having lower back aches since Sunday. Also had a dream last night that I had a positive test.