Dr said no 17 days late

Got bloods done and doctor Saids I'm not <a href="https://play.google.com/store/apps/details?id=com.glow.android.nurture">pregnant app</a> said im 5 weeks 5 days and I'm getting positives at home. like I don't get it. Could doctor be wrong he sent me for an internal ultrasound appointment is on Thursday. But has this happen to anyone else who gone to the doctor have them tell them there not and they ended up actually being pregnant and having a good result? My parenter leeps telling me to have hope bit it's hard. Now I'm 17 days late