if u have long cycle

Those of you who had a 35 day cycle when did you get a BFP. ??? I'm 13dpo  and  bfn  I got positive opk on February 28  cycle day 21  so I know I have long cycle and ovulate late  when should I test again plz help I have some symptoms sore boobs backache diarrhea cervix is high soft and close  I pee a lot af due 3/15 one day until af ?? Plz help thanx ❤️