Im 23 days late on my period..i took a test 17 days after I had sex and it came out negative ?

On the day that I was sappost to start I spotted for a day and for the rest of 2 mire days it was clear duscharge...but then two weeks later I started gettn nausus but not throwing up and I have headaches along with lower backaches I recenly tooka test It still came out negative but like aftet 5 sec....but its been 8 years that I have not been able to come out preggo. .wat else could it be...