Get a blood test at the doctor's office, if there's a chance. More sensitive than a urine test in case your body's just taking a little longer to amp up the hcg. Have you missed any periods or had any abnormal ones?
If you're on birth control, it can cause the symptoms you mention, but since you don't mention birth control, I'm thinking you may not be on it.
I'm stuck on the same boat! Well just that I missed my period too. But I got a negative result also and nobody answers my question either. :/