Too Early or Too Late ?

Beba • Proud Micro Preemie Mom • Currently TTC Baby #2
Went to the doctors today and they did another HPT ... I've done 3 HPT of my own and it's all been negative and with this one is 4 BFN !!! I'm 15-17 days late AF was supposed to come on 4/19 WTh is going on ???? Please someone comment