If repeated pregnancy
tests are negative when performed properly, it could mean that you are not pregnant. Yet, you could benefit from a serum beta-hCG
titre assay which could conclusively exclude/confirm pregnancy. Though you do have some symptoms suggestive of early pregnancy, conclusive evidence is needed to substantiate. If pregnancy is excluded through the blood test
and also a trans-vaginal sonogram, you could be induced to see if you receive a period and further management planned. Hope this helps.