So confused

I used opks this month and i got my super positive on cycle day 20 and 21 (i have 33 to 35 days long cycle) but my cm was super dry . I used to have alot of cm before positive ovulation but then on ovulation days totally dry . I used last month opks and i had cm too with ovulation but this month no cm . Is that normal ? Or could be sign of infertility. I have 4 years old daughter and i had one miscarriage at 8 weeks and one chemical pregnancy all conceived naturally.