Help/Advice??

I have an average of 28 days in my cycle according to my apps, I start CD1 anywhere between 25-33 days.

This month I decided to use OPKs, blue dye AND pink dye. The most consistent with one another to pick a "peak" day would be the 29th of Oct. (CD17). We only did the BD CD14, CD16, and CD19 into the "fertile" window. My projected period date is Nov. 10th with a 28 day expected cycle this month.

I cramped horribly on CD20 for a few minutes, like actually stopping me in my tracks. Now for 2 days I have been cramping and having backaches.

I'm just confused, the 10th wouldn't be enough time for implantation to occur, in the slim chance that I am actually pregnant. Would it??

Do I actually have a chance this cycle? I'm so disheartened that we didn't do the BD on CD18 and that has me completely convinced we are now out.