if the pregnancy
test was negative, then you can be sure that you are not pregnant. this is true even if you drank a lot if fluid. however, there may be some other hormonal
cause that can explain some if your symptoms and why your period had been delayed. if your period does not come back in the next few weeks, you should see your doctor and get some blood tests and possibly an exam which might help explain what is going on. I hope this is helpful, please feel free to ask me if you have any more questions.