I’ve read that the actual process takes 3-5 days to complete before your body begins producing HCG. Is this accurate? Anyone have any info?

I had the strangest pulling feeling 7dpo (only lasted 10 seconds, I’ve never had anything like it before) and when I was looking it up, found it could be implantation. 11dpo with BFN, so I am curious if the process can actually take 3-5 days!