Negative urine test

Hi ladies! As of today I am 8 days late on my period . On day 4 I went to the ER for excruciating pain in my lower stomach and vaginal area . The doctors took urine samples & found no bacteria in my sample . They also gave me a urine pregnancy test but it was negative . My breasts have been sore for the past week . I’m talking about sharp sharp pain in my nipples all the way up my breast & I have a cold right now . Does that sound kinda preggo to anyone ? I couldn’t get a blood test because they couldn’t find any veins . I have an appointment with my OB/GYN on the 20th? Is there a possibility that the urine test could have given me a false negative ? Thanks in advance for your responses.