I'm 7 days late on my period and have major cramping.i took a pregnant test and it came out negative. could it be wrong?

Can repeat in 1 week: A negative urine pregnancy test is a reliable result, if done after missing an expected period. Pelvic and uterine discomfort or cramping can be from a rise in prostaglandin hormones (before a period occurs), but other things can cause symptoms too, such as ovulation pain, constipation, bladder symptoms, an ovarian cyst, endometriosis, etc... One's doctor should evaluate if symptoms continue.