Thanks for the query.
The possibility of pregnancy
is less as both your blood test
and urine pregnancy tests are negative.
The symptoms you are having could be due to hormonal imbalance and some of the symptoms can be due to irritable bowel syndrome
Thinking excessively about the pregnancy can lead to symptoms suggesting pregnancy, called as spurious pregnancy.
So you once consult gynecologist and go for ultrasound
which will help in ruling out the possibility of pregnancy.
For more details you can ask me through: http://www.healthcaremagic.com/doctors/dr-sree-gouri-sr/63429