Advice needed!!!😩

Please help! I am 14 dpo. Tested this morning and bfn. I am on cd 40 and according to opks ovulated the 14th of November... I have no cramps or signs af is coming. Usually I get af 14 days after positive opk.

Has anyone had bfn 14 dpo and then got a positive???

My cycle is so long this month for some reason the only thing we did different was use preseed.

At what point should I consider going to the doctor if af doesn’t show?

Sorry all the questions just super anxious and a getting worried now.

Thanks x