Not meant to scare you, but it could be possible that you are pregnant if you are having all those symptoms...

I knew I was pregnant with my first child but my doctor and four blood test kept on saying NO - well guess what I was right and after two months of going in for a pregnancy blood test every two weeks the test finally came back positive and a ultra sound confirmed it... my baby boy was born nine months after my said date of conception and not that of a stupid blood test that took two months to show up.

Keep us up to date on how things turn out.