Read some stories on google about women being pregnant for months but had negative urine and blood tests. is this even possible?

Only on the internet: Women are pregnant for many, many months with negative bHCG urine and blood tests on the internet. Some pregnant women have regular menstrual periods every month until delivery, on the internet. There are also those guys who suddenly grown 4 inches taller at age 30. The internet is a fascinating place. Of course, these things don't happen in real life.