Could I be pregnant? Need help!?

Hi! Here is the deal: My husband had a vasectomy about 3 yrs ago and I have been having many pregnancy symptoms! First I felt lightheaded for about a week and then noticed darkening around my areolas, blue veins on my , peeing alot more then usual, heartburn, and a heaviness type feeling in my lower abdomen! Oh, and I am over 2 weeks late for my period! I have taken many HPT's and all have shown negative...Went to the doctor this last Monday and he said because husband was fixed there is 0.000% chance I could be pregnant and only ran a pee test which came back negative too! I am going completely bonkers and could use some insight here. I do believe that if I am with-child, that it is a God thing all the way but am now in the middle of looking for a new doctor because the one I was seeing is not up to date on research and all. Any ideas?!?! Please any insight would help me... Thanks