Hello~I would see your gyn, as to the test, sometimes, in the very beginning, they are not that accurate, however, I am not aware of pregnancy symptoms appearing that soon, but every one is different, you certainly have the indications of being pregnant.
Let's rule out being pregnant since you have had periods.
Since UTI can lead to and produce Kidney infections, I would return to your doctor for this evaluation.
Kidney infections can cause dehydration, thus both can produce these symptoms.
You can always call your OB/GYN and ask them to check things out. They can do an ultrasound or blood pregnancy test just to be sure. Are you wanting to get pregnant or terrified you were? Sometimes when we really want to be pregnant or really don't want to be, we trick our minds into believing we exhibit symptoms of pregnancy even when we're not pregnant. If you're really worried, I would just try to get in with your OB/GYN. That's the fastest way to get answers.