I have late period, nausea, cramping, sore breasts, negative pregnancy test, why?

Anovulation. If you didn't ovulate on time or didn't ovulate at all this month, the hormone your body produces can cause all those symptoms. It doesn't mean you can't get pregnant this cycle either so you should repeat the test if your cycle doesn't come. If it lasts for a while, you should talk to your doctor to find out the cause.