Short Luteal Phase - 4 days overdue - BFN

J
Hi everyone, I hoping someone can help. I have a consistent short Luteal phase of 9 days. DH and I have been TTC for 6 months. I'm currently 13dpo with no 'normal' symptoms that AF is going to arrive. 
I've been nauseous, headaches, sore bbs, slight cramping (but it feels different to AF cramps). I don't usually have these symptoms before AF. BBT has remained elevated. 
Every pregnancy test I've done is BFN
Is it just too soon for my BFP? When should I go to the doc for a blood test?
Thanks in advance for the help!