2 negative test but pregnancy symptoms

So I'm 16 days away from next period my last period was 10 days late and it's NEVER late so before it came I took a test on the 10th day and it was negative and then my period came on he 12th day it started out like spotting than got heavier I took another test yesterday and it was negative also I'm usually on a 28 day cycle and it's never late so that was strange and before I tested the first time I was nauseous and dizzy and had lots of sinus problems along with other things and now I'm feeling other symptoms like cramping around my hip areas and sides and like a heaviness in my lower abdomen and it pulling on hips when I walk my boobs have definetly gotten bigger with super greenish blue veins I'm nauseous and have back discomfort

bad headaches

Could the pregnancy test just not be picking it up or what