Lung nodule that didn't look good from petscan

In July while on vaction with my kids I had a tacycardia, during my stay in the hospital they found a 16mm nodule on my left lung. When I got home my Dr. order another CT and was refered tp pulminory, they order a Petscan and I was called yestesday that they need to do a biopsy, so I waiting today for that call. I am scared that since they want to biopsy it that the petscan meant it is cancerous. Does anyone tell me what to exspect. They showed me it was close to my heart. This also scares me because of the location.