I Was Having Symptoms That I Was Pregnant Oct 16

I was having symptoms that I was pregnant oct 16 took a at home pregnancy test and it was positive with one faint line the other darker I called my doctor and went in. They thought I was pregnant too but my urine test they gave me and blood test were both negative. I still haven't gotten my period. December 21st I was still having symptoms that I was pregnant went into the emergency room and I was pregnant could I have been pregnant the whole time since October?