Symptoms of pregnancy combined with negative pregnancy tests may indicate a false pregnancy. This occurs when unconscious desires trigger the hormones.
There are several medical issues which could cause symptoms similar to a pregnancy and you absolutely need to get checked out by a medical professional, preferably your OB/GYN.
Pregnancy tests are not 100% accurate. Even two could be wrong. If you think there is even a slight chance of pregnancy, see you doctor ASAP. Don't hesitate!
Maybe you tested too early, used expired tests, had diluted urine. Also ectopic pregnancies don't show up on a test. Try again in a week, then consult a doctor.