If your symptoms were caused by pregnancy, your tests would be positive.

The negative tests and your period mean you are not pregnant.

A negative blood test indicates you are not pregnant. Symptoms are not a reliable way to diagnose pregnancy, they can mean other things.

I believe you could be.If your taking any diuretics or water pills it can "mess" with a blood test. Also some wemon have some "implantation" bleeding. This can occur around one week after conceptoin, it can last 2-4 days. Some wemon have a menstral during there whole pregnancy, but that is more rare. Every pregnancy can be difrent even for the same women. If you still believe your pregnant and are having sighns of pregnancy then treat your self as such. Get some prenatel vitamins and maby see a doctor for an exam to see if your cervex has turned "blue or purple" this usuly happens around 8 weeks after conception. or an ultrasound will surly set your mind at ease.
Hope this was helpful. Pipsisewah