SO CONFUSED

Amyllia
Ok so, I am on cycle day 31 
17 DPO and 3 days late with NO sign of AF, I've taken a first response with fist morning urin yesterday morning and this morning and had a VERY clear BFN. I feel like my body is playing a joke on me! I'm so confused and desperately want my BFP! I should also mention that I'm very regular and never really late. Someone help me please