18 DPO & Negative Result

This is a rare cycle for me, I started with the shots on CD 3, visit the dr on day 10 and find only two follicles (20) so the dr recommended to wait for the next cycle for the IUI. Still did a Choragon shot the same day to surge and BD the next two days. Now I'm 18 DPO and this morning had a blood test with a negative result (1.2) What's going on? I'm so nervous and usually I'm never this late for AF, should I still hope?