it is possible all tho extremely unlikely that you are pregnant. weirder things have happend.
to be honest i hate doctors at the mo cause there not helping me so i would get a second opinion and maybe get an ultrasound,
you can never be too sure.
also another reason to persue your doc is cause your periods dont just stop unless your going through the menapause (cant spell) but i dont know how old your are or anything,
hope you find your answers
I would probably agree with your Dr but would want to know what would be causing your period to not show. If you do not always have regular cycles, then maybe this is normal. there are alot of things that can effect your cycle, such as stress, medications, etc. Does your Dr want to run tests to fins out more info?
if you doctor told you something.....go with that. we are just strangers over the internet. if you havent gotten your period in 4 months but your getting negative pregnancy tests. your not pregnant.but your doctor should have told you why or at least tried to figure it out