I just don't get it!!

Gemma
My body is messing with me! I have a 27 day cycle like clockwork and get mild cramps on CD1. This month I got my positive opk on CD 13 I've been getting cramps since 3 days before AF was due to arrive(CD 24/ 11DPO) I'm now a day late but still getting BFNs. Come on body sort yourself out. If she's coming I wish she'd just get on with it!!!!